614
these kind of things get complicated when working oscommerce as XOOPS module.
One solution could be to use oscommerce as a stand alone application and not as a module, make a theme for it exactly as the one you have for XOOPS (to keep the same type of graphical design) , make a link to it from xoops; that way you wouldn´t have to mess around with the code that much and add to oscommerce what ever other oscommerce modules you need for it.
there could be other solutions...