Someone told me I cannot mask anything without moving to Kamailio 3.x
- is that the case?
That is the case. However, if you do move to 3.x, you should look into the 'topoh' (topology hiding) module:
http://www.kamailio.org/docs/modules/3.1.x/modules/topoh.html
Ok, thanks a lot / upgrading time!
//Anders