Folks,
I've just updated rtpproxy tarball available at http://www.portaone.com/~sobomax/rtpproxy.tar to include ability to alter location of the command socket (userful if there are multiple SERs running on the same machine, appropriate patches for nathelper were commited into trunk some time ago), as well as an ability to set specific TOS for RTP packets (default is now 0xa0), which can be used to do QoS.
Regards,
Maxim