I am told that if you use the mpgaxis choices in the shuttle pro setup that you can.

and you will have to setup mpg in your screen set too, I did not have any luck, as I have/had mine all working for my mpg dials
Could not get jog or mpg too step for me (center dial does nothing, outer dial worked but would not change axis on button presses)
had to go back to the jog selection for the axis button selections to work for me.
inner and outer dial worked a few revisions ago just fine.

but this did confirm and display what button press i selected as long as i used the mpgaxis option
local inst = mc.mcGetInstance(inst)
local mpg, rc
mpg, rc = mc.mcMpgGetAxis(inst, 1); -- in this case mpg1
mc.mcCntlSetLastError(inst, 'mpg axis = '.. tostring(mpg));
maybe i need a higher number axis selection, as i am using 3 now for mpg's and there might be some conflict with my current ones.