I just got a Behringer UMX61 MIDI controller, having been told it was "plug and play" on a Mac. When I open Garageband, it recognizes that a MIDI device is connected (I'm connecting via USB) but it's not selectable on the input menu. It won't make any sound as is, so obviously something needs to be done. I looked for drivers, but there aren't any for OS X (so much for Mac-compatible). Has anyone used this particular controller? Am I just missing a step or do I have to return the darn thing?