Buddypress on main WP site, Q&A on another site in multisite?

Okay, so I have a multisite installation at http://www.site.com, and I have another site in the network answers.site.com.

I have installed Q&A on answers.site.com and BuddyPress is installed and being used on the network, with the default site of http://www.site.com for the main BuddyPress install.

Users can login to the main BuddyPress site and use the Q&A plugin on answers.site.com to ask and answer questions.

Activity is correctly shown in a user's BuddyPress activity stream.

I need to add the Q&A tab to the BuddyPress user's account though and wondered if I could be given any pointers on how to do this?

Thanks in advance!