Spent over an hour to find this. It works (as far as adding IP Modem), haven't checked tethering capability yet but anyway I can stick it to AT&T I will (they add bogus charges all the time to my bill).
Once you click on IP modem, and click to add a new profile you can go back to regedit and give yourself permission to write to the RAS key and then add the profile, save all your work, then go back in and remove the RAS permissions to write again.