Ok, Daniel!
I am trying exactly what you said, but for some reason the proxy server can't forward the message back to the WebSocket server. I am getting "487 Unresolvable destination". Appears that my Proxy Server can't get data from usrloc.
When I register an user using WebRTC I can see that the system stores the information in kamailio database and in the field "contact" it puts a string. The Proxy server is looking in database and just find this information. Actually, I'm trying to understand the entire process that envolves passing information from an Edge Server to a Proxy server that sends the Register information to another Registrar server (as I described before). The database is shared between all the servers, and they are in the same network.
I just read the information in another topic, as you said, but I think that my case is a lil bit different from it. I you agree, I can post my configuration files here. Maybe this can help another users with the same problem!
Thanks again!!!