protected function _callback(RM_PayPal_Service $provider)
{
$bookingRef = $provider->getBookingRef($provider->ipnData['invoice']);
$transactionInfo = new RM_Payments_Transaction_Info();
$transactionInfo->providerName = 'PayPal';
$transactionInfo->id = $provider->ipnData['txn_id'];
$transactionInfo->reservationID = $bookingRef;
$transactionInfo->statusCode = $provider->ipnData['payment_status'];
$transactionInfo->total = $provider->ipnData['mc_gross'];
$callbackClassName = $provider->ipnData['custom'];
$callbackObject = new $callbackClassName();
$callbackObject->paymentTransactionCallback($transactionInfo);
}