Can you define "doesn't work"? You say you can connect, so how are you determining that it isn't using the wifi network?

@MatthewRead I don't think there's a way to do this in Cy 10. However, I think app developers are able to accomplish this. In the doubleTwist media player app, it has an option to automatically go into Mass Storage for me on USB connect. So I'm sure someone's made an app for this sole purpose. If not, I think you're out of luck. Or install doubleTwist, ;). Sorry.