protected function _handleAuth( $userid,  $password)
    {
        if (!$this->_auth) {
            return true;
        }
        $this->_auth->setCredentials($userid, $password);
        $auth = Zend_Auth::getInstance();
        $result = $auth->authenticate($this->_auth);
        if ($result->isValid()) {
            if (!$this->isSession()) {
                $this->setSession();
            }
            return true;
        } else {
            // authentication failed, good bye
            require_once 'Zend/Amf/Server/Exception.php';
            throw new Zend_Amf_Server_Exception(
                "Authentication failed: " . join("\n",
                    $result->getMessages()), $result->getCode());
        }

    }