You have to provide the SIP trace with all packets from INVITE to the BYE in order to see the routing headers.
Also, it is more appropriate to use <sr-users [at] lists.sip-router.org> mailing list for this kind of needs. The tracker here is intended mainly for bugs in the C code or new feature requests, reaching a smaller group of people, the developers. On sr-users you will get access to the wider community that deals with configuration files.
--- Reply to this email directly or view it on GitHub: https://github.com/kamailio/kamailio/issues/110#issuecomment-82616823