you do not handle credit cards, all that is done by Protx.
I used it before with my own code, and now trying to integrate into OsCommerce. (using VSP Form), not quite there yet.
I will be using PREAUTH so will let you know if I succeed :)
I've had this similar problem. but even after deleting and adding the GBP currency still get zero amounts.
then I added USD as a currency (leaving GBP as default). and then the amounts return. strange.
even stranger is that every time I select a new page the USD amounts show. I must have something wrong with my config.