RF Modulated Changer in '02 Mercedes C230

I'm looking to put a Pioneer RF modulated 6-disc changer into an '02 Mercedes-Benz C230 Kompressor coupe. I went into the back of the panel and removed the passenger side panel to find the Bose box with the factory sub. I was hoping to find the European antenna there with the fiberoptic stuff and the cell phone antenna. I had no such luck, however. I found what appears to be the cell phone antenna connection (it's a coaxial cable with a connection that is screwed together), then there is another similar coaxial connection that is not connected to anything. Other than that (and a serial connector), there is nothing that I can find there to hook into. Any suggestions on where to look or what to do from here? I'm not sure if that coax line that's not connected is the antenna or not -- I'd think if it were the antenna, it'd be hooked up to something (since he's getting reception fine).

Help or suggestions would be greatly appreciated.

my girl has a 02 c230 coupe and the changer works throught the factory head unit and its in the glove box.... hope this helps