I have been dismantleing these alot lately. If you look there should be a notch cut on the ID (inside diameter) of the valve, there is a tempered steel locking ring inside that. If you can take a small flat head screwdriver in there and pry the handle of the screwdriver out pushing the top ring of the tempered ring in to the center of the valves area. **** WARNING **** release the preasure first!!!!!!!! just take an OLD towle and place it over the top of the keg. Then take a blunt object and push the ball in the center down and get ready for the smell of big beer. Once the tempered ring is pushed out to the center, stick another small flat head screwdriver behind it and work your way around till the tempered ring is out. then just twist the ball valve 1/8 of a turn to the counter clock direction and lift out. It may get stinkey and stickey,,,,,,,, but hey what guy doesn't like that?
Oh ya be take your time.... No rush on this.