[Ipstenu (Mika Epstein)]

Easy. You redirect BB presses signup/login to WP and then the WP profile to BB.

Okay, not ‘easy’ but … If you’ve integrated login, you can edit the login links on BBpress so registrations go to WP and then put a couple redirects in your htaccess in case someone gets ‘smart’. You still have people login through BB or WP, but since it’s the same server, it’s all good.