I developed 3 payment modules interfacing with bank gateway.

I thought to enhance my modules (as already wrote in qnother post) managing better the cases when customers, after having payed on bank site, don't come back (for any reason) to Zen Cart store. This way, their cart is still full and oviously no order is created (nor of course e-mailed). My idea was to track this kind of orders (already doing) adding also details on products ordered (this is my next enhancement).

But now I thought, well this would not be needed for those gateways that send back to ZC store transaction results silently (meaning: communication server to server (s2s)) if only I could take those data and create an order. Obviously we must take care of the fact that if we create an order based upon s2s communication, we must find a way to provide a checkout success page for all those customers that come back to our store after having payed (well, all the gateway require a return url, this could be an apposite page, not the standard checkout success page).

Any idea?