Is it possible to connect a USB HDD to an Airport Express that is acting as a network extender for an Airport Extreme base station? I already have a printer connected and it works properly wirelessly. The printer is connected to a powered USB hub and the hub is plugged into the port of the Express. I was trying to plug the USB HDD to the hub and hoping to use it to wirelessly back up my macbook pro. If this wont work, is there some other way that I can use the HDD on a wireless network?