public function setOwner($name = '', $email = '')
    {
        if (!empty($email)) {
        	/**
        	 * @see Zend_Validate_EmailAddress
        	 */
        	require_once 'Zend/Validate/EmailAddress.php';
            $validate = new Zend_Validate_EmailAddress();
            if (!$validate->isValid($email)) {
                /**
                 * @see Zend_Feed_Builder_Exception
                 */
                require_once 'Zend/Feed/Builder/Exception.php';
                throw new Zend_Feed_Builder_Exception("you have to set a valid email address into the itunes owner's email property");
            }
        }
        $this->offsetSet('owner', array('name' => $name, 'email' => $email));
        return $this;
    }