Sounds a little like the experience I had with my Go 920, bought specifically because it could transmit the directions (plus music from my IPod) onto the FM band.
Then they took that facility away because it was illegal, yet they still had their reps on various TV shopping channels using it as a selling point and eventually after getting a bloody patch on the front of my head (banging it against their brick wall called customer service) they eventually revived that service again with no explanation why, seeing it was illegal just months before...