the generally accepted method of removal is to use a pulling tool
one can be bodgied up with a bit of steel and a few bolts.
i think i use a harmonic ballancer pulling tool to get mine off last time
it wasn't perfect but it worked.
if the boss and wheel are to be biffed away i just wriggle and twist and sweat and swear and they usually come off, but there is the risk of busting something that way!
hope that helps somewhat
I took mine off about two weeks ago, after undoing the centre nut it wiggled, swore, banged and finally off it came with a fly! Like Fj40 said, lever it from side to side, it will come, be persistant!
Thing is the momo boss kit stacked.
The steering wheel is slightly off centre, so I'm try to fixing.
Well, it's not too bad.
I changed the wheel, because the original one brocks the view of Speedo but 350mm wheel gives me better view to maters and not too bad handling on and off the road.
Thanks for advice and I'm going to run for supercheap auto/repco sometime today.