Sirius Problems - Need Install Help Please!

[Sarge]

Hi,

I bought a sirius receiver on ebay that is supposed to be compatible with my E70 X5. It is a Gen 2.5 unit, and plugs into the existing 'open' cables in the trunk.

After plugging it in, nothing happens (no SAT option on the input source selector screen)

Does the car need to be programmed?

I checked the contacts on the plug and the sirius module, and everything is clean.

Vehicle is a 2007 X5 4.8i with all OEM equipment:
DVD Nav
rear seat DVD screen (center console)
single slot DVD (in dash)
6 disc changer (in dash)
ANOTHER 6 disc changer (in glove box - why TWO changers?)

The satellite unit i bought was manufactured in April 08 (gen2.5) and the part number shows it is compatible with the E70 X5 (per realoem.com search engine).

Any help would be greatly appreciated, as I live 2 hours from the dealer...

Thanks,

Sarge