I need help to configure RTPProxy.

I have working Kamailio on Centos 6.5, On LAN everything is working fine. Now I want my other users to connect using 3G or any other network.

Please help me with that.

Statis Public IP (DSL Modem) ----- Proxy Box with 2 Lan cards --- 192.168.2.0 and 192.168.0.0 (Lan Side)