I have mapped my VSHG (where the stick registers as a POV Hat) to MAME and having only mapped the four cardinal directions I find no problems with moving diagonally. I also have no problems when I've used JoyToKey to map the POV hat into controlling the mouse. Again, I've only mapped up, down, left and right.
perhaps the intelligence of the programs has been increased from the last time I dared try to map a pov hat. I very distintly remember diagonals turning into a no-op when i just mapped the cardinal directions before.
