Have you removed the shaft that holds the clutch fork in place? look on side of engine, small plug, think its a 10mm alen key, remove this and insert a long threaded bolt to pull shaft out, same thread as the ones in your cam belt cover, if using one of them, dont damage it if you need it again. when shaft out lift up fork to disengage from pressure release bearing. If you have already done the above then its just stuck on, work your way around the top of box where joined to block, with diferent size chisels. but be carfull.