I have a FM transmitter that opperates on 12V @ 500mA. Does anyone how how I can "steal" or combine the power from that device to my shuffle. The shuffle opperates 5V @ 500 mA. I want to be able to just plug the transmitter in and then not have to worry about the battery running out on the shuffle or using 2 DC adpters. Does this make since? Can you help?

Thomas AShworth