Resurrecting an old thread because I had this question last night, and found an answer I'm happier with.
I use
Autohotkey to help with the missing buttons on the type cover, and it turned out great for this.
At the simplest you can add these lines which will enable single-pen-click to next slide, and double-pen-click to go back
#IfWinExist, ahk_class screenClass
#F20:: Send {PgDn}
#F19:: Send {PgUp}
Return
The pen still launches OneNote otherwise.
The only trick was that if you had a slideshow up anywhere it still pushes the keys to the active windows: this ugly but annotated version fixes that
; Use Surface Pen Button as Powerpoint Control
; Kudos for first clues at
http://superuser.com/questions/7771...cation-opened-by-the-surface-pro-3s-pen-butto
; and
http://www.kennylowe.org/2014/09/11/surface-pro-3-pen-button-customisation/
; Only try if in presentation mode (screenClass)
; -so pen launches Onenote as normal at all other times
#IfWinExist, ahk_class screenClass
; F20 is SINGLE click of pen button
#F20::
; check that a powerpoint window is focussed
if (WinActive("ahk_class PPTFrameClass")) or (WinActive("ahk_class screenClass"))
; send Page Down to advance slide
Send {PgDn}
; F19 is DOUBLE click of pen button
#F19::
; check that a powerpoint window is focussed
if (WinActive("ahk_class PPTFrameClass")) or (WinActive("ahk_class screenClass"))
; send Page Up to go to previous slide
Send {PgUp}
Return