Set up payment gateway

I have recently changed credit card processing company from securetrading to netbanx. I need somone to set this up on my web site, initially to run alongside securetrading, then when it is working properly to change it to purely netbanx. I am planning to use [login to view URL] as my cart - at present it is a simple custom order form. The merchant provider is cardsave. I need to be able to process payments from several different websites and to be able to track them properly. At present it seems I can't do that and all processed payments come through to the same page, which is confusing for customers, especially when the products aren't related - this seems to be a limitation of securetrading. Please only bid for this project if you have already have references for very similar projects. My site is [login to view URL] and www.themagicofspain.com. There is a possible additional project to set up shipping costs for order pages via [login to view URL]