/**
 * @class CM_FormField_Hidden
 * @extends CM_FormField_Abstract
 */
var CM_FormField_Hidden = CM_FormField_Abstract.extend({
	_class: 'CM_FormField_Hidden',

	/**
	 * @return String
	 */
	getValue: function() {
		return this.$('input').val();
	},

	/**
	 * @param {String} value
	 */
	setValue: function(value) {
		this.$('input').val(value);
	}
});

/**
 * @class CM_FormField_Hidden
 * @extends CM_FormField_Abstract
 */
var CM_FormField_Hidden = CM_FormField_Abstract.extend({
	_class: 'CM_FormField_Hidden'
});
--- 
+++ 
@@ -3,5 +3,19 @@
  * @extends CM_FormField_Abstract
  */
 var CM_FormField_Hidden = CM_FormField_Abstract.extend({
-	_class: 'CM_FormField_Hidden'
+	_class: 'CM_FormField_Hidden',
+
+	/**
+	 * @return String
+	 */
+	getValue: function() {
+		return this.$('input').val();
+	},
+
+	/**
+	 * @param {String} value
+	 */
+	setValue: function(value) {
+		this.$('input').val(value);
+	}
 });
Add value getter/setter for hidden form field
