All I can say is DO NOT hold the cover in a vice the way it is shown in the video. Do as TMM said and put it flat on a flat surface and knock it out. DO NOT pry against the outer flange.
You have to be smarter than the screwdriver! LOL One thing about working on old cars (or anything for that matter) you need to figure out how things work and how they come apart. Otherwise you should pay someone to repair it.
