XM antenna adapter for Chevy trucks

I have an 04 chevy that came with the factory GM radio.  I recently installed a alpine head unit and today bought the upgrade XM 2 piece kit for the alpine system.  Does anyone know of an adapter that I can use to use my factory mounted XM antenna versus the  one that comes in the after market kit.  It just looks stupid having two antennas on the truck.

if you're not going to use the factory antenna; you could gut the old antenna housing and put your new one inside; should just be a fiberglass or plastic housing. Life moves pretty fast; if you don't stop and look around once in a while; you could miss it.

The factory antenna plugs right into aftermarket tuners. we have done many of them using the factory antenna. Jazzy

Well it doesn't on my 04.  There is three connectors that plug into the factory radio.  The wiring harness that contains power, speaker wires, etc; the FM antenna; and what I assume to be the plug that contains the XM antenna, which is a square/rectangle plug with several wires in it.  The antenna connection on the XM box I bough is a lot smaller, and it has a round connecter on it.  There is nothing like this on the factory radio or any harness that connected to it.

the factory xm antenna goes to the factory xm tuner behind the glove box. there is a small rectangle connector with the 2 satellite antennas on it plugged into the tuner. you can remove the satellite antenna ends from connector and plug one of the antennas into the aftermarket xm reciever or get an adapter to make the 2 antenna ends into 1 end.

Thanks alot.  I didn't know there was "another" box.  I'll go look for it.