[Serusers] SER proxy behind NAT

Hello. Recently I've been fighting with SER running on local IP, which is statically mapped to public one via NAT/firewall. The problem was in SER putting local IP into Record-route field. Therefore, a public client (X-lite) was trying to send BYE message to this local IP. I used record_route_preset("<SER public IP>") in place of record_route() to solve the problem. Does someone have any comments on the method? Are there any other solutions, (despite the obvious one to put SER into public Internet)? Usage of record_route_preset() is not recommended by the docs. Wouldn't it brake anything? ...Bye..Dmitry.