BuddyPress.org

I think you are saying that your member’s forum posts do not have the author name on them.

From /buddypress/bp-forums/installation-readme.txt

11. Enable user switching in bbPress by copying the following line of code into your bbPress bb-config.php file:

$bb->bb_xmlrpc_allow_user_switching = true;

Put the above line into your bb-config.file. It doesn’t matter where.