Thats pretty much what I want to do (btw: Do you have the source to that) except that I want it to be done with drag and drop and not such pretty graphics in the end .

PS: I have managed to get most of this working quite well, in fact I'm only a few short steps away from having something to show off. The hardest part now is drawing an arc from a known 3 points (Center, Start, and End) knowing that the Arc might not be a true circular piece.