Howdy,
Its possible 🙂
It should be the same combo as your mouse. Holding down Alt and the middle mouse button (MMB) you have mapped to your wacom pen, whilst moving the pen left/right or up/down. Its been a while since I’ve used my wacom, so if the combo isn’t working with Alt, try it without (i.e. hold the MMB equivalent on your pen and move it left/right or up/down on the tablet). Both have to be down whilst over the viewer, otherwise it will zoom in/out when done over the DAG (node graph). Zooming works a little differently in 3D view (btw).
Give that a try, let me know how you go.
Shite, look at the time.. I need a beer.
Cheers,
Doodle