MSRPChat: fix bug in send_message

darcs-hash:20090226091153-b2873-cd4c0a56f9f36a0bcfb04c26b08f588e6bbc8348
MSRPChat fix incorrect usage of get_connector/get_acceptor

darcs-hash:20090226094121-b2873-95d7e6db7a65f1e95222336c780bec1da584e901