Can't view the picture for somereason....
The P.S. pulley torques against the balanceshaft belt sprocket, which pushes against the cam belt sprocket which puts pressure on the oil pump drive, via a flat washer
I strongly suggest getting a 944 flywheel lock from out host:
http://www.pelicanparts.com/catalog/shopcart/PORS/POR_PORS_PTOOLS_pg6.htm#item35
They are $47 It really makes like much easier
I would also inspect your oil pressure relief valve for any foreign debris that may hang it open as well