303854 Zencart and SMF bridge

I need a script or instruction on how to integrate logins zencart with Simple Machines Forum (SMF) such as zencart can do with PHPBB by default. As a result, users can login either in zencart or smf and can gain access to both sides and new users will show up on smf. My zencart is version 1.38a and smf version 1.1.8. This should be a fairly simple task for someone with experienced shopping cart programing and other login integrations. Please provide example(s) if you have them.