I will follow up with the breakdown in the next couple days, but here's a word file with the "how to" on hiding and routing an aftermarket satellite radio antenna.
Magnetic antennas WILL scratch your paint. This mod eliminates that danger by mounting your antenna to the PLASTIC brake light. An extra special added bonus - it hides the wiring through existing holes (no routing the wire through the back window!).
I routed a Sirius antenna, but this should work for XM as well.
*see attached WORD DOC file*
OK, apparently 1.31MB is too big to directly attach, so here's a link to my site.
Satellite Radio Antenna Hiding Mod