I have Sirius satellite, but basically the same animal. You can get an adapter to run it into your am/fm through the antenna wire. Basically your antenna wire plugs into a box, and the box plugs into the stereo, and has a wire that plugs into your docking station for the XM.
Or, the way mine is wired is in the aux port on the radio. direct. When you switch the stereo over to aux, its satellite radio.
'87 YJ, 4.2L built and bored, 8.5" of lift, 8.8 rear, AX15/NP 231, Tom Woods drive shafts, Flat fenders, 12,000LB winch, Custom bumpers, Rattle can paint job. Never completed...