Google analytics for Paypal and Credit cart payments

I am working on Zen-Cart Site. Google Analytics is working fine but the problem I am having is in the ecommerce section of开发者_如何学Go analytics. When I log into my analytics account and I go into the ecommerce section it only gives me sales that were generated through google checkout. If any sale was generated by credit card payment or by paypal that transaction is not registered in analytics. Now I really need to know which products are being sold through all transactions on the site and I'm not getting that info properly because it only tells me which products are being sold through google checkout. How can I do this?

most sites like paypal give you the ability to have the user be redirected back to a specific page after the sale takes place. On that page (usually a "thanks for buying my stuff" page), you need to put your global GA code, as well as some custom GA code to pass info like revenue, product id(s), etc...

You can learn more about what custom GA code to put on that page at this link:

http://code.google.com/intl/en/apis/analytics/docs/tracking/gaTrackingEcommerce.html