Need help setting up payment module

[tralli]

I'm not sure what module to use for this, I've installed CGEcommerceBase but I need some paymentgateway module. The site I'm working on has SSL certificate and the payment transaction must be done on the site itself. Can I use PaypalGateway module and modify it or do you suggest some other method? There are several variables I need to send the creditcard company such as cardinfo, customerinfo and such, I'm not very knowledgable about the cmsms module structure, what part of the module would I have to edit so these info get delivered to the credit card company. I've done this with pure php and html, but doing it via cmsms baffles me.
Please help

[stevew]

Check out the AuthNetAim and AuthNetSim modules - they might do what you want to do.