I would like to see a better way to do this too: At the moment the only option seems to be to put a FXO/FXS adapter between the phone and the POTS port of the router, to then make UPC change the POTS call back to a VOIP call and route it seems a bit crazy.
On the basis UPC have the charging and billing mechanism set up, if they let us access the VOIP service directly then they could have the revenue from it rather than forcing us to use another VOIP provider and give them the revenue