diff -r 5e7a0fedabdf -r 877f952ae2bd web/lib/Zend/Json/Server.php
--- a/web/lib/Zend/Json/Server.php	Thu Mar 21 17:31:31 2013 +0100
+++ b/web/lib/Zend/Json/Server.php	Thu Mar 21 19:50:53 2013 +0100
@@ -14,9 +14,9 @@
  *
  * @category   Zend
  * @package    Zend_Json
- * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
+ * @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: Server.php 22237 2010-05-21 23:58:00Z andyfowler $
+ * @version    $Id: Server.php 25085 2012-11-06 21:11:41Z rob $
  */
 
 /**
@@ -27,7 +27,7 @@
 /**
  * @category   Zend
  * @package    Zend_Json
- * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
+ * @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 Zend_Json_Server extends Zend_Server_Abstract
@@ -534,8 +534,8 @@
                 $reflection = new ReflectionFunction( $callback->getFunction() );
                 $refParams  = $reflection->getParameters();
             } else {
-                
-                $reflection = new ReflectionMethod( 
+
+                $reflection = new ReflectionMethod(
                     $callback->getClass(),
                     $callback->getMethod()
                 );
@@ -547,11 +547,11 @@
                 if( isset( $params[ $refParam->getName() ] ) ) {
                     $orderedParams[ $refParam->getName() ] = $params[ $refParam->getName() ];
                 } elseif( $refParam->isOptional() ) {
-                    $orderedParams[ $refParam->getName() ] = null;
+                    $orderedParams[ $refParam->getName() ] = $refParam->getDefaultValue();
                 } else {
-                    throw new Zend_Server_Exception( 
-                        'Missing required parameter: ' . $refParam->getName() 
-                    ); 
+                    throw new Zend_Server_Exception(
+                        'Missing required parameter: ' . $refParam->getName()
+                    );
                 }
             }
             $params = $orderedParams;