@Graham: the vcards are generated by the addressbook code of the n900. The obexd daemon requests the vcards from there and transfers them to your carkit. So if you think the N: filed is wrong, this is caused by the n900 addressbook server.

@andrew_1967: There is nothing to be brave about. The wiki (see post 1 in this thread) clearly states how to install the 2 needed packages.