|clipperqb, If you look very closely at the lower right picture you will see that it's that small cable that carries the video. The jack that it plugs into is labeled 'Video output'.|
And I believe that the 'RGB <--> Composite' switch refers to that cable and not the 9 pin connector above it.
I don't believe any company would use a connector that is universally used for serial ports for some other purpose.
I suspect that getting (or building) an adapter for that special cable would be extremely difficult.