Just because you have the Bose Premium sound doesn't mean you have all the components to receive XM. Unless you paid for the Infotainment package that comes with BOSE & XM then you don't have everything you need. All 2004 radios are "XM Ready", but don't have all the hardware for XM. The difference between 04's and the previous years is that the 04 Bose radio can control and show song information on the display for XM. All previous MY's you have to buy an adaptor which only allows for the XM sound to be channeled throught the stock radio system, but you still couldn't control the changing of channels and see song information in the screen.
The bottom line is, you can order Bose without having all the XM hardware. You should have been given your XM Receiver ID number at the time of purchase. This is the number you need to use to activate your XM subscription. If you don'thave one, then chances are you don't have all the hardware for XM to work.