Had the same issue a few months back, got too excited trying to pry the drive plate with a screwdriver when removing the back wheel for the first time. I nicked the seal and she was leaking fairly bad. I did as the guys here directed and used a small nail and put a hole in the seal, threaded in a small screw and then pulled the seal out by the screw. Lube up the new seal with gear oil and pressed in place by hand. All is well. I think the manual leads you down a different & more difficult route. It was really quite simple.
