I just bought a 2007 991S that has an XM Radio installed. The stock radio is still there. The XM Radio is installed in the little cubby space below the radio. I need to turn the radio on to get the ID so I can get a new subscription. Does any one know how to do this? Do I turn the stock radio on and hit an auxiliary button or something? The guy I bought it from claims to have never turned it on. Thanks!