[SR-Users] Issue with INVITE to NATed client

[Iskren Hadzhinedev]

Hi list!

I'm using kamailio 4.2 for load-balancing and failover via dispatcher, 
but I'm having some NAT related issues and I was hoping that someone 
might point me in the right direction.
My setup is the following:

PSTN - PBX - kamailio - NAT - client

Calls from the NATed client to PSTN and/or PBX features (e.g. voicemail) 
work just fine.
However, when a call comes from PSTN to the client, kamailio sends the 
INVITE to the client's RFC1918 IP and I can't figure out how to send it 
to the correct destination. I tried loading the registrar and usrloc 
modules and used save("location") during REGISTER and lookup("location") 
just before loose_route(), but the end result was that kamailio replied 
to REGISTERs with any username/password with a 200 OK and the endpoints 
never registered with the PBX.
I can attach the config file if that will help.

Thanks for all input in advance!

Regards,
Iskren