AutoCAD 2010 :: Wintab Compatible Digitizer - Your Pointing Device Cannot Be Used As Tablet

We're trying to use vtablet with ACAD 2012LT and a GTCO Rollup III 3648 on Com1, 32-bit Win7 (32-bit driver) and are having a bit of trouble with the configuration.The problem is that ACAD seems to only half-recognize it.

When we try to change the pointing device to "wintab compatible digitizer", the change won't "stick" - but I don't see an error message in the status line.  The "apply" button simply continues to stay grayed out and clicking on "ok" doesn't make ACAD save the change.  Thus since the pointing device remains a mouse, when we try to turn the tablet on, we get an error message that says "your pointing device cannot be used as a tablet".

However, we can move the tablet's stylus and it moves the cursor.  We can also draw a line in ACAD but can't calibrate (since calibrate never becomes an option since we can't turn the tablet on inside ACAD).

Yes, UAC is off.  Yes the digitizer does seem to be sending regular packets.  Yes the digitizer shows up in device manager as a MS Serial Ballpoint (the mouse uses USB).  They both move the cursor seemingly without conflict (there is no jerkiness).