[SR-Users] rtpproxy and CANCEL in serial forked scenarios

Hi, I ran into a scenario with couple of serial forks where kamailio loops to itself and, due to the looping, the INVITE to a new branch happens before the CANCEL to an old branch. What I do at the moment is force rtpproxy in branch route, and stop rtpproxy in the failure route. The problem with this scenario is that in rtpproxy_offer and unforce_rtpproxy, the rtpproxy module only passes the call-id and from-tag to rtpproxy (because there is no to-tag yet), which then in unforce_rtpproxy for a CANCEL deletes all calls related to it (because it can only match on from-tag and call-id, obviously). This means that when I do a subsequent rtpproxy_answer for my new branch, rtpproxy doesn't find the session anymore, since it has been removed with the CANCEL. A fix I can think of is to also pass the branch of the top-most via to rtpproxy in order to perform a more fine-grained matching. Are there solutions to that out there somewhere, or is it something I should just introduce, eg. as a new param to offer/answer/unforce functions? Objections? Other approaches? Andreas