diff --git a/src/Symfony/Components/DependencyInjection/BuilderConfiguration.php b/src/Symfony/Components/DependencyInjection/BuilderConfiguration.php
index 9c79b5c073..e74b445f88 100644
--- a/src/Symfony/Components/DependencyInjection/BuilderConfiguration.php
+++ b/src/Symfony/Components/DependencyInjection/BuilderConfiguration.php
@@ -265,4 +265,25 @@ class BuilderConfiguration
 
     return $this->definitions[$id];
   }
+
+  /**
+   * Gets a service definition by id or alias.
+   *
+   * The method "unaliases" recursively to return a Definition instance.
+   *
+   * @param  string  $id The service identifier or alias
+   *
+   * @return Definition A Definition instance
+   *
+   * @throws \InvalidArgumentException if the service definition does not exist
+   */
+  public function findDefinition($id)
+  {
+    if ($this->hasAlias($id))
+    {
+      return $this->findDefinition($this->getAlias($id));
+    }
+
+    return $this->getDefinition($id);
+  }
 }
diff --git a/src/Symfony/Components/DependencyInjection/Loader/Extension/SymfonyTemplatingExtension.php b/src/Symfony/Components/DependencyInjection/Loader/Extension/SymfonyTemplatingExtension.php
index 1ffdab6d47..e6531811a0 100644
--- a/src/Symfony/Components/DependencyInjection/Loader/Extension/SymfonyTemplatingExtension.php
+++ b/src/Symfony/Components/DependencyInjection/Loader/Extension/SymfonyTemplatingExtension.php
@@ -97,8 +97,8 @@ class SymfonyTemplatingExtension extends LoaderExtension
     if (isset($config['cache']))
     {
       // wrap the loader with some cache
-      $configuration->setAlias('symfony.templating.loader.wrapped', $configuration->getAlias('symfony.templating.loader'));
-      $configuration->setAlias('symfony.templating.loader', 'symfony.templating.loader.cache');
+      $configuration->setDefinition('symfony.templating.loader.wrapped', $configuration->findDefinition('symfony.templating.loader'));
+      $configuration->setDefinition('symfony.templating.loader', $configuration->getDefinition('symfony.templating.loader.cache'));
       $configuration->setParameter('symfony.templating.loader.cache.path', $config['cache']);
     }
 
diff --git a/tests/unit/Symfony/Components/DependencyInjection/BuilderConfigurationTest.php b/tests/unit/Symfony/Components/DependencyInjection/BuilderConfigurationTest.php
new file mode 100644
index 0000000000..faf48acce9
--- /dev/null
+++ b/tests/unit/Symfony/Components/DependencyInjection/BuilderConfigurationTest.php
@@ -0,0 +1,177 @@
+<?php
+
+/*
+ * This file is part of the symfony package.
+ * (c) Fabien Potencier <fabien.potencier@symfony-project.com>
+ * 
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+require_once __DIR__.'/../../../bootstrap.php';
+
+use Symfony\Components\DependencyInjection\Builder;
+use Symfony\Components\DependencyInjection\BuilderConfiguration;
+use Symfony\Components\DependencyInjection\Definition;
+use Symfony\Components\DependencyInjection\Reference;
+
+$fixturesPath = __DIR__.'/../../../../fixtures/Symfony/Components/DependencyInjection/';
+
+$t = new LimeTest(1);
+
+// __construct()
+$t->diag('__construct()');
+$definitions = array(
+  'foo' => new Definition('FooClass'),
+  'bar' => new Definition('BarClass'),
+);
+$parameters = array(
+  'foo' => 'foo',
+  'bar' => 'bar',
+);
+$configuration = new BuilderConfiguration($definitions, $parameters);
+$t->is($configuration->getDefinitions(), $definitions, '__construct() takes an array of definitions as its first argument');
+$t->is($configuration->getParameters(), $parameters, '__construct() takes an array of parameters as its second argument');
+
+// ->merge()
+$t->diag('->merge()');
+$configuration = new BuilderConfiguration();
+$configuration->merge(null);
+$t->is($configuration->getParameters(), array(), '->merge() accepts null as an argument');
+$t->is($configuration->getDefinitions(), array(), '->merge() accepts null as an argument');
+
+$configuration = new BuilderConfiguration(array(), array('bar' => 'foo'));
+$configuration1 = new BuilderConfiguration(array(), array('foo' => 'bar'));
+$configuration->merge($configuration1);
+$t->is($configuration->getParameters(), array('bar' => 'foo', 'foo' => 'bar'), '->merge() merges current parameters with the loaded ones');
+
+$configuration = new BuilderConfiguration(array(), array('bar' => 'foo', 'foo' => 'baz'));
+$config = new BuilderConfiguration(array(), array('foo' => 'bar'));
+$configuration->merge($config);
+$t->is($configuration->getParameters(), array('bar' => 'foo', 'foo' => 'bar'), '->merge() overrides existing parameters');
+
+$configuration = new BuilderConfiguration(array('foo' => new Definition('FooClass'), 'bar' => new Definition('BarClass')));
+$config = new BuilderConfiguration(array('baz' => new Definition('BazClass')));
+$config->setAlias('alias_for_foo', 'foo');
+$configuration->merge($config);
+$t->is(array_keys($configuration->getDefinitions()), array('foo', 'bar', 'baz'), '->merge() merges definitions already defined ones');
+$t->is($configuration->getAliases(), array('alias_for_foo' => 'foo'), '->merge() registers defined aliases');
+
+$configuration = new BuilderConfiguration(array('foo' => new Definition('FooClass')));
+$config->setDefinition('foo', new Definition('BazClass'));
+$configuration->merge($config);
+$t->is($configuration->getDefinition('foo')->getClass(), 'BazClass', '->merge() overrides already defined services');
+
+// ->setParameters() ->getParameters()
+$t->diag('->setParameters() ->getParameters()');
+
+$configuration = new BuilderConfiguration();
+$t->is($configuration->getParameters(), array(), '->getParameters() returns an empty array if no parameter has been defined');
+
+$configuration->setParameters(array('foo' => 'bar'));
+$t->is($configuration->getParameters(), array('foo' => 'bar'), '->setParameters() sets the parameters');
+
+$configuration->setParameters(array('bar' => 'foo'));
+$t->is($configuration->getParameters(), array('bar' => 'foo'), '->setParameters() overrides the previous defined parameters');
+
+$configuration->setParameters(array('Bar' => 'foo'));
+$t->is($configuration->getParameters(), array('bar' => 'foo'), '->setParameters() converts the key to lowercase');
+
+// ->setParameter() ->getParameter()
+$t->diag('->setParameter() ->getParameter() ');
+
+$configuration = new BuilderConfiguration(array(), array('foo' => 'bar'));
+$configuration->setParameter('bar', 'foo');
+$t->is($configuration->getParameter('bar'), 'foo', '->setParameter() sets the value of a new parameter');
+
+$configuration->setParameter('foo', 'baz');
+$t->is($configuration->getParameter('foo'), 'baz', '->setParameter() overrides previously set parameter');
+
+$configuration->setParameter('Foo', 'baz1');
+$t->is($configuration->getParameter('foo'), 'baz1', '->setParameter() converts the key to lowercase');
+$t->is($configuration->getParameter('FOO'), 'baz1', '->getParameter() converts the key to lowercase');
+
+try
+{
+  $configuration->getParameter('baba');
+  $t->fail('->getParameter() throws an \InvalidArgumentException if the key does not exist');
+}
+catch (\InvalidArgumentException $e)
+{
+  $t->pass('->getParameter() throws an \InvalidArgumentException if the key does not exist');
+}
+
+// ->hasParameter()
+$t->diag('->hasParameter()');
+$configuration = new BuilderConfiguration(array(), array('foo' => 'bar'));
+$t->ok($configuration->hasParameter('foo'), '->hasParameter() returns true if a parameter is defined');
+$t->ok($configuration->hasParameter('Foo'), '->hasParameter() converts the key to lowercase');
+$t->ok(!$configuration->hasParameter('bar'), '->hasParameter() returns false if a parameter is not defined');
+
+// ->addParameters()
+$t->diag('->addParameters()');
+$configuration = new BuilderConfiguration(array(), array('foo' => 'bar'));
+$configuration->addParameters(array('bar' => 'foo'));
+$t->is($configuration->getParameters(), array('foo' => 'bar', 'bar' => 'foo'), '->addParameters() adds parameters to the existing ones');
+$configuration->addParameters(array('Bar' => 'fooz'));
+$t->is($configuration->getParameters(), array('foo' => 'bar', 'bar' => 'fooz'), '->addParameters() converts keys to lowercase');
+
+// ->setAlias() ->getAlias() ->hasAlias() ->getAliases() ->addAliases()
+$t->diag('->setAlias() ->getAlias() ->hasAlias()');
+$configuration = new BuilderConfiguration();
+$configuration->setAlias('bar', 'foo');
+$t->is($configuration->getAlias('bar'), 'foo', '->setAlias() defines a new alias');
+$t->ok($configuration->hasAlias('bar'), '->hasAlias() returns true if the alias is defined');
+$t->ok(!$configuration->hasAlias('baba'), '->hasAlias() returns false if the alias is not defined');
+
+try
+{
+  $configuration->getAlias('baba');
+  $t->fail('->getAlias() throws an \InvalidArgumentException if the alias does not exist');
+}
+catch (\InvalidArgumentException $e)
+{
+  $t->pass('->getAlias() throws an \InvalidArgumentException if the alias does not exist');
+}
+
+$configuration->setAlias('barbar', 'foofoo');
+$t->is($configuration->getAliases(), array('bar' => 'foo', 'barbar' => 'foofoo'), '->getAliases() returns an array of all defined aliases');
+
+$configuration->addAliases(array('foo' => 'bar'));
+$t->is($configuration->getAliases(), array('bar' => 'foo', 'barbar' => 'foofoo', 'foo' => 'bar'), '->addAliases() adds some aliases');
+
+// ->setDefinitions() ->addDefinitions() ->getDefinitions() ->setDefinition() ->getDefinition() ->hasDefinition()
+$t->diag('->setDefinitions() ->addDefinitions() ->getDefinitions() ->setDefinition() ->getDefinition() ->hasDefinition()');
+$configuration = new BuilderConfiguration();
+$definitions = array(
+  'foo' => new Definition('FooClass'),
+  'bar' => new Definition('BarClass'),
+);
+$configuration->setDefinitions($definitions);
+$t->is($configuration->getDefinitions(), $definitions, '->setDefinitions() sets the service definitions');
+$t->ok($configuration->hasDefinition('foo'), '->hasDefinition() returns true if a service definition exists');
+$t->ok(!$configuration->hasDefinition('foobar'), '->hasDefinition() returns false if a service definition does not exist');
+
+$configuration->setDefinition('foobar', $foo = new Definition('FooBarClass'));
+$t->is($configuration->getDefinition('foobar'), $foo, '->getDefinition() returns a service definition if defined');
+$t->ok($configuration->setDefinition('foobar', $foo = new Definition('FooBarClass')) === $foo, '->setDefinition() implements a fuild interface by returning the service reference');
+
+$configuration->addDefinitions($defs = array('foobar' => new Definition('FooBarClass')));
+$t->is($configuration->getDefinitions(), array_merge($definitions, $defs), '->addDefinitions() adds the service definitions');
+
+try
+{
+  $configuration->getDefinition('baz');
+  $t->fail('->getDefinition() throws an InvalidArgumentException if the service definition does not exist');
+}
+catch (InvalidArgumentException $e)
+{
+  $t->pass('->getDefinition() throws an InvalidArgumentException if the service definition does not exist');
+}
+
+// ->findDefinition()
+$t->diag('->findDefinition()');
+$configuration = new BuilderConfiguration(array('foo' => $definition = new Definition('FooClass')));
+$configuration->setAlias('bar', 'foo');
+$configuration->setAlias('foobar', 'bar');
+$t->is($configuration->findDefinition('foobar'), $definition, '->findDefinition() returns a Definition');
diff --git a/tests/unit/Symfony/Components/DependencyInjection/BuilderTest.php b/tests/unit/Symfony/Components/DependencyInjection/BuilderTest.php
index 085c21134e..c23462613d 100644
--- a/tests/unit/Symfony/Components/DependencyInjection/BuilderTest.php
+++ b/tests/unit/Symfony/Components/DependencyInjection/BuilderTest.php
@@ -269,7 +269,7 @@ $config = new BuilderConfiguration();
 $config->setDefinition('baz', new Definition('BazClass'));
 $config->setAlias('alias_for_foo', 'foo');
 $container->merge($config);
-$t->is(array_keys($container->getDefinitions()), array('foo', 'bar', 'baz'), '->load() merges definitions already defined ones');
+$t->is(array_keys($container->getDefinitions()), array('foo', 'bar', 'baz'), '->merge() merges definitions already defined ones');
 $t->is($container->getAliases(), array('alias_for_foo' => 'foo'), '->merge() registers defined aliases');
 
 $container = new Builder();