wacom - Area drawing - Huion Tablet

I've tried everything here on ask ubuntu and found good solutions for tablets drawing of HUION brand. However I have a problem that I believe has not been resolved:

I have the H420 HUION tablet and put it in ubuntu 12:04 LTS it works normal but the area is drawing on the screen is equivalent to a portion of it, say. (starting from the left top edge), and the same occurs with useful drawing area on the tablet itself.

In my case, my monitor is 1368x768 and it seems that the drawing area is only 346 pixels wide by 192 pixels high (values ​​only for you to understand better what happens)

I installed the drivers WizardPen, calibrated and managed to resolve the drawing area on the monitor, but the tablet functional area remains small (the area of the drawing tablet is too small, the pen works up to a point and discards the rest of the area)

I would like to help.