[Serusers] Forwarding to port 5060 when UA behind NAT

Dear list, I have situation where SIP UA is behind NAT, that maps everything to ports above number 61000. I use nathelper, rtpproxy and SER 0.8.12. Everything works fine. Until I have UA that does not send "Contact" field in BYE (or OK for BYE) during call termination. In this case SER is forwarding responses not to NAT-ed port, but to port 5060. QUESTION: What can be done to correct this situation? Is this improved in new SER releases? Sequence is as follows: IP_of_A:61001 -> IP_of_proxy:5060 BYE sip:B@IP_of_proxy loose_route ... IP_of_proxy:5060 -> IP_of_B:5060 BYE sip:B@IP_of_B ... IP_of_B:5060 -> IP_of_proxy:5060 SIP/2.0 200 OK ... IP_of_proxy:5060 -> IP_of_A:5060 <WRONG! Should be 61001> SIP/2.0 200 OK ... It does not happen when terminating UA sends "Contact" field in first BYE. -- Regards, Arek Bekiersz