diff --git a/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateTimeToStringTransformer.php b/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateTimeToStringTransformer.php
index 41eea327a3..cbaac96859 100644
--- a/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateTimeToStringTransformer.php
+++ b/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateTimeToStringTransformer.php
@@ -39,23 +39,38 @@ class DateTimeToStringTransformer extends BaseDateTimeTransformer
      */
     private $parseFormat;
 
+    /**
+     * Whether to parse by appending a pipe "|" to the parse format.
+     *
+     * This only works as of PHP 5.3.8.
+     *
+     * @var Boolean
+     */
+    private $parseUsingPipe;
+
     /**
      * Transforms a \DateTime instance to a string
      *
      * @see \DateTime::format() for supported formats
      *
-     * @param string $inputTimezone  The name of the input timezone
-     * @param string $outputTimezone The name of the output timezone
-     * @param string $format         The date format
+     * @param string  $inputTimezone  The name of the input timezone
+     * @param string  $outputTimezone The name of the output timezone
+     * @param string  $format         The date format
+     * @param Boolean $parseUsingPipe Whether to parse by appending a pipe "|" to the parse format
      *
      * @throws UnexpectedTypeException if a timezone is not a string
      */
-    public function __construct($inputTimezone = null, $outputTimezone = null, $format = 'Y-m-d H:i:s')
+    public function __construct($inputTimezone = null, $outputTimezone = null, $format = 'Y-m-d H:i:s', $parseUsingPipe = null)
     {
         parent::__construct($inputTimezone, $outputTimezone);
 
         $this->generateFormat = $this->parseFormat = $format;
 
+        // The pipe in the parser pattern only works as of PHP 5.3.8
+        $this->parseUsingPipe = null === $parseUsingPipe
+            ? version_compare(phpversion(), '5.3.8', '>=')
+            : $parseUsingPipe;
+
         // See http://php.net/manual/en/datetime.createfromformat.php
         // The character "|" in the format makes sure that the parts of a date
         // that are *not* specified in the format are reset to the corresponding
@@ -64,7 +79,7 @@ class DateTimeToStringTransformer extends BaseDateTimeTransformer
         // where the time corresponds to the current server time.
         // With "|" and "Y-m-d", "2010-02-03" becomes "2010-02-03 00:00:00",
         // which is at least deterministic and thus used here.
-        if (false === strpos($this->parseFormat, '|')) {
+        if ($this->parseUsingPipe && false === strpos($this->parseFormat, '|')) {
             $this->parseFormat .= '|';
         }
     }
@@ -125,6 +140,70 @@ class DateTimeToStringTransformer extends BaseDateTimeTransformer
             $outputTz = new \DateTimeZone($this->outputTimezone);
             $dateTime = \DateTime::createFromFormat($this->parseFormat, $value, $outputTz);
 
+            // On PHP versions < 5.3.8 we need to emulate the pipe operator
+            // and reset parts not given in the format to their equivalent
+            // of the UNIX base timestamp.
+            if (!$this->parseUsingPipe) {
+                list($year, $month, $day, $hour, $minute, $second) = explode('-', $dateTime->format('Y-m-d-H-i-s'));
+
+                // Check which of the date parts are present in the pattern
+                preg_match(
+                    '/(' .
+                    '(?<day>[djDl])|' .
+                    '(?<month>[FMmn])|' .
+                    '(?<year>[Yy])|' .
+                    '(?<hour>[ghGH])|' .
+                    '(?<minute>i)|' .
+                    '(?<second>s)|' .
+                    '(?<dayofyear>z)|' .
+                    '(?<timestamp>U)|' .
+                    '[^djDlFMmnYyghGHiszU]' .
+                    ')*/',
+                    $this->parseFormat,
+                    $matches
+                );
+
+                // preg_match() does not guarantee to set all indices, so
+                // set them unless given
+                $matches = array_merge(array(
+                    'day' => false,
+                    'month' => false,
+                    'year' => false,
+                    'hour' => false,
+                    'minute' => false,
+                    'second' => false,
+                    'dayofyear' => false,
+                    'timestamp' => false,
+                ), $matches);
+
+                // Reset all parts that don't exist in the format to the
+                // corresponding part of the UNIX base timestamp
+                if (!$matches['timestamp']) {
+                    if (!$matches['dayofyear']) {
+                        if (!$matches['day']) {
+                            $day = 1;
+                        }
+                        if (!$matches['month']) {
+                            $month = 1;
+                        }
+                    }
+                    if (!$matches['year']) {
+                        $year = 1970;
+                    }
+                    if (!$matches['hour']) {
+                        $hour = 0;
+                    }
+                    if (!$matches['minute']) {
+                        $minute = 0;
+                    }
+                    if (!$matches['second']) {
+                        $second = 0;
+                    }
+                    $dateTime->setDate($year, $month, $day);
+                    $dateTime->setTime($hour, $minute, $second);
+                }
+            }
+
             $lastErrors = \DateTime::getLastErrors();
 
             if (0 < $lastErrors['warning_count'] || 0 < $lastErrors['error_count']) {
diff --git a/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/DateTimeToStringTransformerTest.php b/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/DateTimeToStringTransformerTest.php
index 893c4c2bfd..804549fd80 100644
--- a/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/DateTimeToStringTransformerTest.php
+++ b/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/DateTimeToStringTransformerTest.php
@@ -18,18 +18,43 @@ class DateTimeToStringTransformerTest extends DateTimeTestCase
     public function dataProvider()
     {
         return array(
-            array('Y-m-d H:i:s', '2010-02-03 04:05:06', '2010-02-03 04:05:06 UTC'),
-            array('Y-m-d H:i:00', '2010-02-03 04:05:00', '2010-02-03 04:05:00 UTC'),
-            array('Y-m-d H:i', '2010-02-03 04:05', '2010-02-03 04:05:00 UTC'),
-            array('Y-m-d H', '2010-02-03 04', '2010-02-03 04:00:00 UTC'),
+            array('Y-m-d H:i:s', '2010-02-03 16:05:06', '2010-02-03 16:05:06 UTC'),
+            array('Y-m-d H:i:00', '2010-02-03 16:05:00', '2010-02-03 16:05:00 UTC'),
+            array('Y-m-d H:i', '2010-02-03 16:05', '2010-02-03 16:05:00 UTC'),
+            array('Y-m-d H', '2010-02-03 16', '2010-02-03 16:00:00 UTC'),
             array('Y-m-d', '2010-02-03', '2010-02-03 00:00:00 UTC'),
             array('Y-m', '2010-02', '2010-02-01 00:00:00 UTC'),
             array('Y', '2010', '2010-01-01 00:00:00 UTC'),
             array('d-m-Y', '03-02-2010', '2010-02-03 00:00:00 UTC'),
-            array('H:i:s', '04:05:06', '1970-01-01 04:05:06 UTC'),
-            array('H:i:00', '04:05:00', '1970-01-01 04:05:00 UTC'),
-            array('H:i', '04:05', '1970-01-01 04:05:00 UTC'),
-            array('H', '04', '1970-01-01 04:00:00 UTC'),
+            array('H:i:s', '16:05:06', '1970-01-01 16:05:06 UTC'),
+            array('H:i:00', '16:05:00', '1970-01-01 16:05:00 UTC'),
+            array('H:i', '16:05', '1970-01-01 16:05:00 UTC'),
+            array('H', '16', '1970-01-01 16:00:00 UTC'),
+
+            // different day representations
+            array('Y-m-j', '2010-02-3', '2010-02-03 00:00:00 UTC'),
+            array('Y-z', '2010-33', '2010-02-03 00:00:00 UTC'),
+            array('z', '33', '1970-02-03 00:00:00 UTC'),
+
+            // not bijective
+            //array('Y-m-D', '2010-02-Wed', '2010-02-03 00:00:00 UTC'),
+            //array('Y-m-l', '2010-02-Wednesday', '2010-02-03 00:00:00 UTC'),
+
+            // different month representations
+            array('Y-n-d', '2010-2-03', '2010-02-03 00:00:00 UTC'),
+            array('Y-M-d', '2010-Feb-03', '2010-02-03 00:00:00 UTC'),
+            array('Y-F-d', '2010-February-03', '2010-02-03 00:00:00 UTC'),
+
+            // different year representations
+            array('y-m-d', '10-02-03', '2010-02-03 00:00:00 UTC'),
+
+            // different time representations
+            array('G:i:s', '16:05:06', '1970-01-01 16:05:06 UTC'),
+            array('g:i:s a', '4:05:06 pm', '1970-01-01 16:05:06 UTC'),
+            array('h:i:s a', '04:05:06 pm', '1970-01-01 16:05:06 UTC'),
+
+            // seconds since unix
+            array('U', '1265213106', '2010-02-03 16:05:06 UTC'),
         );
     }
 
@@ -75,8 +100,24 @@ class DateTimeToStringTransformerTest extends DateTimeTestCase
     /**
      * @dataProvider dataProvider
      */
-    public function testReverseTransform($format, $input, $output)
+    public function testReverseTransformBeforePhp538($format, $input, $output)
     {
+        $reverseTransformer = new DateTimeToStringTransformer('UTC', 'UTC', $format, false);
+
+        $output = new \DateTime($output);
+
+        $this->assertDateTimeEquals($output, $reverseTransformer->reverseTransform($input));
+    }
+
+    /**
+     * @dataProvider dataProvider
+     */
+    public function testReverseTransformAsOfPhp538($format, $input, $output)
+    {
+        if (version_compare(phpversion(), '5.3.8', '<')) {
+            $this->markTestSkipped('Requires PHP 5.3.8 or newer');
+        }
+
         $reverseTransformer = new DateTimeToStringTransformer('UTC', 'UTC', $format);
 
         $output = new \DateTime($output);
@@ -95,7 +136,7 @@ class DateTimeToStringTransformerTest extends DateTimeTestCase
     {
         $reverseTransformer = new DateTimeToStringTransformer('America/New_York', 'Asia/Hong_Kong', 'Y-m-d H:i:s');
 
-        $output = new \DateTime('2010-02-03 04:05:06 Asia/Hong_Kong');
+        $output = new \DateTime('2010-02-03 16:05:06 Asia/Hong_Kong');
         $input = $output->format('Y-m-d H:i:s');
         $output->setTimeZone(new \DateTimeZone('America/New_York'));