[Users] Openser and Mediaproxy behind NAT

Hi All, I am new to Openser and propably answer to my question is very simple.. I,ve been trying to run Openser with Mediaroxy behind NAT (they both work on a same machine with a private IP - 192.168.1.x). I am connected to internet through ADSL router (dynamic IP). I ve tried few configurations and I cant get it to work - I have "no audio problem" with nated users who register from outside of my LAN. I ve read that mediaproxy must listen on a public IP address, but first I thought that this is just a matter of port forwarding. And here is my question: Is it possible for this to work with described configuration? (Openser with mediaproxy both behind NAT) I ve used similar solution with Asterisk and Xtunnels and it worked fine. Thanks in advance and sorry for my English:). Best regards, Maciek Kowalski