Hi Laurens, I used an adjustable angle grinder tool to remove the little cover in the centre of the flywheel. Be careful as it's a left hand thread from memory.
My motor came with the flywheel puller, so I used that with a plumbing tool to remove the flywheel (I don't recall why I had the vice grips on there):
If you're not on there already, join the Yahoo group for "Ducati Pushrod Singles". You will find lots of information to help you out over there.
Do you have a build thread here?
I still haven't made any further progress yet...