[Users] proxy authorization required sent to the wrong port

Hello! I've tried to modify my setup to use rtpproxy, following the guide posted at http://siprouter.onsip.org/doc/gettingstarted/, most of it works fine, but i have a small but annoying problem: When i receive a invite from a UA, i verify the identity with proxy_authorize. However, the proxy-authenticate-request is not sent to the originating sip-port of the UA but to 5060 for some reason. In my old setup this worked flawless, the proxy authorize request is sent to the correct external port of the phone. To me it seems there is no difference in this part of the route-plan, so how does this happen? I have attached both config-files and a ngrep of the requests(*.old is the working setup, *.rtpproxy is the new setup that doesn't work), maybe someone can help me with this? Thanks in advance! Regards Christian