[SR-Users] RTPProxy and premature RTP

I'm having some troubles with a provider sending RTP before a 183 Session Progress or 200 OK (I see up to 1s of rtp prematurely). The machine is running rtpproxy and apparently rtpproxy buffers these rtp packets and flushed them in one burst when the 183/200 arrive, this creates havock in some endpoints but is undesirable in all cases IMHO if the delay of the 182/200 is to high (>0.1s).

Is there a way to control buffering/flushing from kamailio? Is rebuilding rtpproxy with a smaller buffer an option? Or should I switch to an other proxy module? Any thoughts about this subject (apart from getting the provider to stop sending premature rtp)?