diff --git a/tests/Zend/Form/Element/CaptchaTest.php b/tests/Zend/Form/Element/CaptchaTest.php
index 6ca4426..8d0ab93 100644
--- a/tests/Zend/Form/Element/CaptchaTest.php
+++ b/tests/Zend/Form/Element/CaptchaTest.php
@@ -388,6 +388,36 @@ class Zend_Form_Element_CaptchaTest extends PHPUnit_Framework_TestCase
             var_export($decorators, true)
         );
     }
+    
+    /**
+     * @group ZF-12173
+     */
+    public function testShouldAllowAddingCaptchaPrefixPathWithBackslash()
+    {
+        if (version_compare(PHP_VERSION, '5.3.0', '<')) {
+            $this->markTestSkipped(__CLASS__ . '::' . __METHOD__ . ' requires PHP 5.3.0 or greater');
+            return;
+        }
+        $this->element->addPrefixPath('My\Captcha', 'My/Captcha/', 'captcha');
+        $loader = $this->element->getPluginLoader('captcha');
+        $paths  = $loader->getPaths('My\Captcha');
+        $this->assertTrue(is_array($paths));
+    }
+    
+    /**
+     * @group ZF-12173
+     */
+    public function testAddingCaptchaPrefixPathWithBackslash()
+    {
+        if (version_compare(PHP_VERSION, '5.3.0', '<')) {
+            $this->markTestSkipped(__CLASS__ . '::' . __METHOD__ . ' requires PHP 5.3.0 or greater');
+            return;
+        }
+        $this->element->addPrefixPath('My\\', 'My/');
+        $loader = $this->element->getPluginLoader('captcha');
+        $paths  = $loader->getPaths('My\Captcha');
+        $this->assertTrue(is_array($paths));
+    }
 }
 
 /**
diff --git a/tests/Zend/Form/Element/FileTest.php b/tests/Zend/Form/Element/FileTest.php
index 2ff3a48..b6703e0 100644
--- a/tests/Zend/Form/Element/FileTest.php
+++ b/tests/Zend/Form/Element/FileTest.php
@@ -491,6 +491,21 @@ class Zend_Form_Element_FileTest extends PHPUnit_Framework_TestCase
     {
         $this->assertSame($this->element, $this->element->loadDefaultDecorators());
     }
+    
+    /**
+     * @group ZF-12173
+     */
+    public function testElementShouldAllowAdapterWithBackslahes()
+    {
+        if (version_compare(PHP_VERSION, '5.3.0', '<')) {
+            $this->markTestSkipped(__CLASS__ . '::' . __METHOD__ . ' requires PHP 5.3.0 or greater');
+            return;
+        }
+        $this->element->addPrefixPath('Zend\Form\Element\FileTest\Adapter', dirname(__FILE__) . '/_files/TransferAdapter', 'transfer_adapter');
+        $this->element->setTransferAdapter('Bar');
+        $test = $this->element->getTransferAdapter();
+        $this->assertTrue($test instanceof \Zend\Form\Element\FileTest\Adapter\Bar);
+    }
 }
 
 class Zend_Form_Element_FileTest_MockAdapter extends Zend_File_Transfer_Adapter_Abstract
diff --git a/tests/Zend/Form/Element/_files/TransferAdapter/Bar.php b/tests/Zend/Form/Element/_files/TransferAdapter/Bar.php
new file mode 100644
index 0000000..ebd46bb
--- /dev/null
+++ b/tests/Zend/Form/Element/_files/TransferAdapter/Bar.php
@@ -0,0 +1,70 @@
+<?php
+/**
+ * Zend Framework
+ *
+ * LICENSE
+ *
+ * This source file is subject to the new BSD license that is bundled
+ * with this package in the file LICENSE.txt.
+ * It is also available through the world-wide-web at this URL:
+ * http://framework.zend.com/license/new-bsd
+ * If you did not receive a copy of the license and are unable to
+ * obtain it through the world-wide-web, please send an email
+ * to license@zend.com so we can send you a copy immediately.
+ *
+ * @category   Zend
+ * @package    Zend_Form
+ * @subpackage UnitTests
+ * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license    http://framework.zend.com/license/new-bsd     New BSD License
+ * @version    $Id$
+ */
+namespace Zend\Form\Element\FileTest\Adapter;
+
+/**
+ * @category   Zend
+ * @package    Zend_Form
+ * @subpackage UnitTests
+ * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license    http://framework.zend.com/license/new-bsd     New BSD License
+ */
+class Bar extends \Zend_File_Transfer_Adapter_Abstract
+{
+    public $received = false;
+
+    public function send($options = null)
+    {
+        return;
+    }
+
+    public function receive($options = null)
+    {
+        $this->received = true;
+        return;
+    }
+
+    public function isSent($file = null)
+    {
+        return false;
+    }
+
+    public function isReceived($file = null)
+    {
+        return $this->received;
+    }
+
+    public function isUploaded($files = null)
+    {
+        return true;
+    }
+
+    public function isFiltered($files = null)
+    {
+        return true;
+    }
+
+    public static function getProgress()
+    {
+        return;
+    }
+}
diff --git a/tests/Zend/Form/ElementTest.php b/tests/Zend/Form/ElementTest.php
index f673e3a..9bc3bf2 100644
--- a/tests/Zend/Form/ElementTest.php
+++ b/tests/Zend/Form/ElementTest.php
@@ -2189,6 +2189,36 @@ class Zend_Form_ElementTest extends PHPUnit_Framework_TestCase
         $validator = $username->getValidator('regex');
         $this->assertTrue($validator->zfBreakChainOnFailure);
     }
+    
+    /**
+     * @group ZF-12173
+     */
+    public function testCanAddPluginLoaderPrefixPathsWithBackslashes()
+    {
+        if (version_compare(PHP_VERSION, '5.3.0', '<')) {
+            $this->markTestSkipped(__CLASS__ . '::' . __METHOD__ . ' requires PHP 5.3.0 or greater');
+            return;
+        }
+        $validatorLoader = new Zend_Loader_PluginLoader();
+        $filterLoader    = new Zend_Loader_PluginLoader();
+        $decoratorLoader = new Zend_Loader_PluginLoader();
+        $this->element->setPluginLoader($validatorLoader, 'validate')
+                      ->setPluginLoader($filterLoader, 'filter')
+                      ->setPluginLoader($decoratorLoader, 'decorator')
+                      ->addPrefixPath('Zf\Foo', 'Zf/Foo');
+
+        $paths = $filterLoader->getPaths('Zf\Foo\Filter');
+        $this->assertTrue(is_array($paths));
+        $this->assertContains('Filter', $paths[0]);
+
+        $paths = $validatorLoader->getPaths('Zf\Foo\Validate');
+        $this->assertTrue(is_array($paths));
+        $this->assertContains('Validate', $paths[0]);
+
+        $paths = $decoratorLoader->getPaths('Zf\Foo\Decorator');
+        $this->assertTrue(is_array($paths), var_export($paths, 1));
+        $this->assertContains('Decorator', $paths[0]);
+    }
 }
 
 class Zend_Form_ElementTest_Decorator extends Zend_Form_Decorator_Abstract
diff --git a/tests/Zend/Form/FormTest.php b/tests/Zend/Form/FormTest.php
index 609ee14..c21ab37 100644
--- a/tests/Zend/Form/FormTest.php
+++ b/tests/Zend/Form/FormTest.php
@@ -4534,6 +4534,26 @@ class Zend_Form_FormTest extends PHPUnit_Framework_TestCase
             'SubForm element received wrong validator'
         );        
     }
+
+    /**
+     * @group ZF-12173
+     */
+    public function testAddingPrefixPathsWithBackslashWillLoadNamespacedPlugins()
+    {
+        if (version_compare(PHP_VERSION, '5.3.0', '<')) {
+            $this->markTestSkipped(__CLASS__ . '::' . __METHOD__ . ' requires PHP 5.3.0 or greater');
+            return;
+        }
+        $form = new Zend_Form();
+        $form->addPrefixPath('Zf\Foo', 'Zf/Foo');
+        foreach (array('element', 'decorator') as $type) {
+            $loader = $form->getPluginLoader($type);
+            $paths = $loader->getPaths('Zf\Foo\\' . ucfirst($type));
+            $this->assertTrue(is_array($paths), "Failed for type $type: " . var_export($paths, 1));
+            $this->assertFalse(empty($paths));
+            $this->assertContains('Foo', $paths[0]);
+        }
+    }
 }
 
 class Zend_Form_FormTest_DisplayGroup extends Zend_Form_DisplayGroup