If you are using a BB's registration, you should be able to disable the login/logout/register menu items, or you should be able point to the BB's login/logout/register page(s).
In 2.3, with phpBB 2, it calls the photopost classifieds login when somebody tries to do somehting like access the uploadproduct.php without being logged in first. It does not link to the phpBB 2 login. I can send screenshots if you need them.
Well, in those cases we do ask for a user to login (when they aren't logged in while trying to upload). But the regsiter/logout/login links in the menu itself do link to the phpBB2 side.
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