[Serusers] RTPproxy and SER

Hi all, I'm trying to use RTPproxy (CVS) and SER to enable locally-routed endpoints to talk to an external public gateway. When a call comes from the external gateway, the SDP in the INVITE gets rewritten properly with SER's IP address, but then when my phone hangs off, the SDP in the 200 OK doesn't get rewritten, so an RFC1918 IP address is passed to the external gateway (so I get no audio). I'm using nathelper with: modparam("nathelper", "rtpproxy_sock", "unix:/var/run/rtpproxy.sock") and for my tests I put "force_rtp_proxy()" at the very beginning of the routing logic in order to make sure it gets invoked. But the SDP in the 200 OK is not rewritten no matter what. Is this a know issue? Is there a known workaround? Thanks in advance for any help, -- Alexandre Aractingi <aaractingi(a)libertysurf.fr>