Just a note: I've made one of this based on the very same diagram, but I've read that the bulb should be on the focus, not on the shutter, and it's true.
Because if you're going to shoot on bulb, when you focus the image and shoot through the bulb switch, when you release the focus button the shutter open again. That means, if you want to get bulb pictures, you cannot focus to shoot, you have to use manual focus or have focused previously.
So, connect the bulb on the focus and when take bulb pictures, activate the switch and press the shutter button of the control to take the photo.
Hope I've helped.
