Payment Modules have to follow your business guidelines in the same way Shipping Modules do. The default osCommerce setup unfortunately does not cater to the following three indispensable options:
Hide Payment Modules from public eyes (while you test them in their future home, not a development site)
Create dependencies between Shipping Modules and Payment Modules
Offer customized payment options for selected customers
This chapter provides you with the necessary code snippets to implement all of the above. After trying out the following recipes, you will agree that the Payment Modules that used to appear completely static are, in fact highly flexible, and able to react to your shop's profile.