How to listen to Infuse 4G through USB speakers

[phbarringer]

I got a nice deck for my car the other day, and it has a USB input. No matter what USB setting I put my Infuse 4G on (debugging, Kies, media player, or mass storage) I can't get it to play through the deck. It recognizes the device, but won't find any media. I've tried Music Player, Cubed, and using Allshare (though I'm not sure I did that correctly). Any ideas? Maybe an app that would make it sync properly or a setting I need to change?