Finger/Stylus differentiation for multi-touch digitizer

Hello,

I need to write a filter driver for a multi-touch digitizer that would differentiate between finger and stylus input based on the area of contact, and report stylus touch input as mouse input.
I wrote a device upper filter driver which successfully separates finger from stylus inputs, but I’m stuck regarding the mouse input reporting.
The device supports the mouse mode, so can I switch the device mode on the fly (but it sounds like it’s the wrong direction), should I make my filter driver as filtering also the mouse device so that I can inject my “fake” reports to it’s queue ?

Thanks