I've been using the cradle for a few weeks now, and correct, no media access, which I don't care about because I dedicate a 160gb iPod in the car via the USB port.
But the signal strength is definitely improved. When I connect it in less than ideal signal areas, the signal strength increases. Disconnect it, and it decreases. So somehow, the sharfin is in use.
So from this perspective, I'm pleased.