I have a 2010 VW Golf. It has an "aux input" and the sales lady said it's capable of playing the iPod through the speakers. I bought the cord (which looks like a wire with a headphone jack at each end) and plugged it in, pressed play on the iPod, but i can't figure out how to get it to play through the car's speakers. There's no button on the radio controls, there's only AM, FM, and CD. Anyone have any ideas?