The keys work but, as explained on the manual, if you redefine them (they are the standard Slew keys), they will follow your new assignment.
the numeric keys (I have on NumLock) move the point of view but not the elements.
Exactly as in default FSX behavior, which GSX hasn't changed, in order to have the numeric keys functioning as Slew, you have to turn NumLock OFF, otherwise they'll control the panning views.