Has anyone successfully used a USB keyboard with the Aluratek Cinepad AT107F? I've had my Aluratek for a month now and like it a lot. However, I'd like a keyboard for those times I'm on the road and want to type in a long e-mail. The touch screen keypad is nice for short replies, but ... I've looked at the cases that are on Amazon that include a USB keyboard, but don't want to buy something that doesn't work with my tablet. I know I could return it if it didn't work, but for some of the units, the return shipping would be almost as much as the cost of the case/keyboard unit.