You have to configure most of this manually, I'm afraid. On your main router, forward ports 80, 443, and 4125 to your repeater. On your repeater, forward them to your server. Then go through the remote access setup wizard, saying that you'll manually configure
your router at the appropriate point.
You should also look around; there's a hotfix that you need to install on your server to keep Remote Access working without error messages after the end of the year.
I'm not on the WHS team, I just post a lot. :)