[Users] Can't replace duplicate c= lines in SDP

Hello everyone, I've already noticed a few posts on that topic, but none has been answered up to resolution of the problem. Here is the issue : I am receiving SDP in INVITEs from a Cisco AS5350 (IOS 12.4) gateway that contain two identical c= lines for the same media. When using force_rtp_proxy, only the last one is replaced by my proxy IP. If I use the mangler module on top of it, then both are replaced, but the one already replaced by force_rtp_proxy is now a concatenation of twice the proxy IP address. Is there a way to deal with this so that both lines are replaced ? Depending on which equipement gets the REQUEST next, either the first or the second line is used, and this leads to RTP proxy problems. Best Regards, Jerome Martin