Yes. I've made sure that both mainmenu and usermenu are set for "All."
Timeline went like this:
1. Create phpbb board with attach_mod
2. Install CB
3. Create wrapper page for phpbb board and cb details usermenu item (everything ok at this point)
4. Install phpbb plugin-connector (everything still ok)
5. Sync users (menus disappear - but just on cb details page and with email notify turned off the registration confirmation page - i've since turned on email confirm to try and bypass this page for first-time users.)
I must be missing something simple.
Here's a link to the site (i removed the cb details usermenu item - can put it back if you like).
www.rsrf.org/antibodies_forum