I finally figured out how to tap the lines coming from my unused Sirius receiver (no subscription) in my speed6 to hardwire my F500 directly to the SAT button on my stock radio. I'll compile and post details if anyone is actually interested.

 

BTW, the F500 wedges perfectly into the mid-dash storage compartment. I didn't need wire, tape, or anything to hold it in place! Almost looks like it's supposed to be there!