That's not how it's done -- you duplicate the layer with the over-the-shoulder shot. You put the duplicated layer ABOVE the corner pin layer. Oops! You can't see the corner pin any more! How do you fix that? You animate a feathered mask around the shoulder and any other parts of the shot that you don't want to be obscured by the corner pin. The process is known as rotoscoping.... and it's not much fun. It takes a lot of time and detail work.
Sorry! No magic wand solutions for this kind of shot!
