/**
  * get all folders for ActiveSync
  *
  * @param string|Expressomail_Model_Account $_account
  * @return array
  */
 public function getFoldersAS($_account)
 {
     $account = $_account instanceof Expressomail_Model_Account ? $_account : Expressomail_Controller_Account::getInstance()->get($_account);
     return $this->_backend->getAllFoldersAS($account);
 }