i have a "dating site" that requires users to create an account/log-in in order to access user profiles. I want to offer the users various membership products through Zen Cart. How do I integrate zen cart into my site and allow the session and log-in information created by my dating site to be re-used by Zen-cart? i don't want my users to have to relog into the Zen cart just to make a payment. Any ideas and examples would be greatly appreciated.