http://vitotechnology.com/en/products/buttonmapper.html
On the site it says: for e-book applications you can set this button to turn over pages (single press for scroll down, press'n'hold for scroll up).
How do you do this? Changing the configuration for ubook reader to scroll left, right, down with ubook in full screen still makes it function "normally".
In my case, button 1 is still opening up file explorer and button 4 still minimizing to the today screen.