[Serusers] ReTransmission of CANCELs on 0.9.7

Hi All, Has anyone come up against an issue on 0.9.6 / 0.9.7 whereby a SIP App Server, delivers a CANCEL to the SER. The SER proxies the CANCELs to all the forked endpoints. At the same time it sends "200 Cancelling" back to the SIP App server...(this suppresses CANCEL retransmission from the SIP App server). If one of the CANCELs from the SER to the SIP UA gets lost....the phone keeps ringing. There is no CANCEL retransmission on the SER !!! There is CANCEL retransmission on the SIP App, but when it sends SER replies "no pending branches" Ideally want the SER do CANCEL retransmissions. I understand the timers were rewritten in 0.10.x but this is not hardened version like 0.9.6....any suggestions? Thanks in advance Rupert