I've read that "The easiest way to insert an entry for a person into BBDB is to press : (colon) in the Summary buffer when a message from him is the selected one. If the person is in the database already, nothing happens; otherwise, Emacs asks you if you want to insert him into the database."
That does not work for me, I guess because I'm using BBDB 3.
EDIT: ':' runs the command 'bbdb-mua-display-sender'.
Is there a workaround to this?