map all XO buttons to different functions

There are 8 buttons on the XO when it is in bookreader mode, four on each side of the display. Right both sets of 4 buttons map to the same 4 functions. The rocker wheel on the left should mape to a different 4 things, so that one can manage more of the basic reading functions without opening the laptop to use the keyboard and mouse.

Ideas : zoom in/out, flip forward/back, scroll up/down, fit-to-screen, return to home-view.
If there are more features desired, save the eight of these as a shift/function key to get 14 functions in all (perhaps one key combo for each link/option in the navigation)