keyDownEvent with Graffiti characters

[Chow, Walter]

Hi,

According to the documentation, the keyDownEvent will be
sent when the user enters the Graffiti characters, pressing 
any button below the display or tap any icon in the icons area.
However, I want to process the keyDownEvent only if the user
enters the Graffiti characters which will include A-Z, a-z, 0-9 and
all the other puntucations.  I wonder if there is a way to detect this
case.  Any information is greatly appreciated.  Thanks in advance.

Walter