The HP document explains how to get dual-touch events at the Windows message level. This works as documented (even outside the TouchSmart environment). But many things are not addressed:

 1) What should be the return code when I process one of these messages? Will this affect what happens to the event?

 2) Should I call the default window procedure?

 3) If I get a dual-touch event, will I also get a WM_MOUSEMOVE, etc.? Is this dependent on the answers to questions 1 and 2?

 4) What if I get a standard mouse-down message first, turn on CaptureMouse, and then put my second finger down? What events will I get?

 5) Will I always get a mouse-down before a mouse-move?

6) Will I always get a mouse-up after a mouse-down? After a mouse-move?

These are all important considerations for anything more than trivial use of dual touch.