cart checkout not supporting notify type payment processors?

[ozminskisj]

I'm sure this question is related to the Paypal Standard not working question https://forum.civicrm.org/index.php/topic,34613.msg147033.html#msg147033 posted last month.

I am creating a Payment Processor modeled after PaymentExpress, which is a notify type Payment Processor that uses the doTransferCheckout function call for the payment processor object derived from CRM_Core_Payment.  When I set up an event to use this payment processor, and I have civiCRM 4.5.2 configured without cart support, the event shows a Register button, and the doTransferCheckout function eventually gets called.  If I configure civiCRM to "Use Shopping Cart Style Event Registration" in Administer\CiviEvent\CiviEvent Component Settings, then the event shows an Add to Cart button and I have to add a menu item to add a link to the system to invoke "?page=CiviCRM&q=civicrm/event/view_cart" for the checkout process.  When I try to checkout, the make_payment function in the CRM_Event_Cart_Form_Checkout_Payment object in CRM\Event\Cart\Form\Checkout\Payment.php calls doDirectPayment() for my payment processor, which is a payment function naturally not implemented in a notify type Payment Processor. 

Is there some code I am supposed to write to override make_payment() so it will call doTransferCheckout instead of doDirectPayment?  Is the new Shopping Cart functionality for Events designed to only support form type payment processors and not button or notify type payment processors?

[petednz]

Never used it. You read the associated stuff eg

"This feature allows users to register for more than one event at a time. When enabled, users will add event(s) to a "cart" and then pay for them all at once. Enabling this setting will affect online registration for all active events. The code is an alpha state, and you will potentially need to have developer resources to debug and fix sections of the codebase while testing and deploying it"

and, esp the bugs bit at end of ...

http://wiki.civicrm.org/confluence/display/CRMDOC/CiviEvent+Cart+Checkout

Also - do you have a StackExchange account?