I have USB trackball/iPac 2 kit connected to a 5v powered USB hub. These are not recognized by the piplay at all. If I plug in a keyboard, the keyboard works. If I plug the iPac into my Mac and run a ROM it works fine. All software on the piplay is up to date.
can you get to the console? Plug the ipac in and type 'dmesg' to see that it gets recognized. Don't remember which ipac I'm using, but it shows up as an HID keyboard.