AbleCommerce Shopping Cart Software

I've managed to shoe-horn authorize functionality into the AbleCommerce payment gateway setup (for RealEx), but not i'm faced with adding 3D validation - this means an initial request to RealEx which is transferred to the card company, a return to the AbleCommerce installation and a form requesting a password from the user, which is then relayed to the card company, and finally the authorization of payment..

In short, it's a bit different from the logic for a simple authorize.

Has anyone else implemented this validation before?

OK - 3D validation..

Here's what has to happen..

The user submits their credit card details - an XML message is created with some of the fields and send to your payment gateway, who forwards the message onto your bank - an xml response stating whether the user is enrolled or not is returned - if they are enrolled, the application must create and post a web form on the fly with a series of hidden fields, including the return url and base 64 encoded credit card data - the user is taken to a web page on their bank's site, requesting their password - if all is well, a response xml is returned to the application, in which case the "DoAuthorize" can proceed..

Now, given the "/checkout/creditcardpaymentpage.ascx" and bespoke payment gateway dll setup, should I try to call functions from the doauthorize function? can i use server.transfer and context.add to programmatically call and pass data to a new aspx which will take this data and post onload?