Despite what Microsoft says in this faq you can do remote assistance through two NAT routers. I learned how to do this last year and it comes in handy if you need to support family and friends remotely when you both are behind NAT routers. (Which by the way, you should be
)
1. You will need the remote users internal ip address and the wan address.
2. Walk the remote user through setting up their router to forward port 3389 TCP to their internal ip address.
3. Have the remote user send you an invitation via email.
4. Save the rcBuddy.MsRcIncident file to your hard drive some where easy to find.
5. Open rcBuddy.MsRcIncident in your favorite text editor.
6. Find the RCTICKET attribute and change the ip address inside to the remote users wan ip address
7. Save the file
8. Then double click the rcBuddy.MsRcIncident file and go through the motions.
9. And cross your fingers.