Heh, so I went to look and see how hard it would be to simulate mouse scrolling, and the answer is... none. Literally none. Because X11 "mouse scroll" events are represented as button presses. Mouse buttons are 1=left, 2=middle, 3=right, 4=scroll-up, 5=scroll-down. So you just stick the relevant lines in your keynavrc; ex.

   i click 4                                                                                                                             
   e click 5                                                                                                                             

That said, I may make an effort to document this better.