Using external touchscreen

I have connected a ViewSonic TD2220 touch screen LCD to an Android computer that has no monitor of it's own (HDMI to output to an external monitor).

The home screen comes up and is displayed correctly. With a wireless keyboard and mouse I can interact with it, open apps and configure settings.

The touch screen part of it does not work however. I have connected via USB the screen to the Android computer (same as I do to get it to work with a PC), but no touch.

I realize this is a driver issue. I have searched for drivers w/o any success. I have also searched for touch screen monitors that support Android - not sure I have found any, at least not in a 22 inch form factor (my requirement).

Does anyone know of touch screens that actually do work with Android? Or, a driver that would work with this ViewSonic model?