Capturing mouse events in PDFWindow

I'm working on an application with an embedded PDFWindow, similar to this example:

www.daniweb.com/code/snippet618.html

I would like to capture the mouse coordinates within the PDFWindow when the left mouse button is clicked. However, it seems that mouse events are not propagated up from the ActiveX container. The goal is to capture a region of the screen which the user selects by clicking and dragging. Any suggestions would be very much appreciated.

Steve