I know it's not exactly the answer you were looking for, and you seem to have already figured it out (great job, by the way), but it's just too much of a coincidence to pass up the opportunity.
I just uploaded my first video to YouTube. It was a video I took at the Woodworking in America conference of Frank Klausz cutting a through mortise with his wonderful pig-sticker chisel. http://www.youtube.com/watch?v=k0__5IukABc
And for a unique viewpoint for Frank cutting a mortise, check out the video of him mortising under glass. Roy Underhill set up a demonstration where Frank cut a mortise where one side was a glass plate. This allows you to see what's going on inside the joint as he whacks away on his chisel. It's really cool.