Removing the camshaft pully

[brainbug007]

Hi guys I'm still working on getting the head off to renew my gaskets and replace the timing belt and I'm struggling to work out how to get the camshaft pully off? The haynes manual mentions using an "improvised" tool to hold it while you loosen the bolt holding the pulley but doesn't really give a good picture or description. I tried jamming some screwdrivers through the pulley against the head but that didn't really seem to work (they almost got pulled in behind the pulley).