How do I locate the sirius antenna wire in back of the radio? I'm planning on getting a 'dock and play' kit to use in my 2011 4R as well as 3 other vehicles and a home docking station. I want to use the existing sirius antenna on my 4R, so I need to find and hopefully unplug the wire that goes into the factory radio. Is it necessary to remove the radio to find it? If so, how do I remove the radio? Thanks.