e-commerce

Payment wizard and e-commerce templates. Must be done using PHP wherever possible. I have a system where clients can choose their preferred payment gateway, or, select multiple payment gateways. It must then display the fields for them to paste in the API, secret key, code etc. Then write the payment outcome back to my applications cart. Then additional e-commerce php pages that will be used as temnplates, however, it must be built with variables linked directly to the database or an XML / JSON page so that when changes are made. They must be immediate. I already have one design that can be used to speed up other templates.