When I took out my gearbox, I put i on semi to facilitate the extrication. Put it back in the exact same way, and I dint play around the the selector switch/lever because there is no reason to. I'll look at it tonight.
EDIT: took some pictures, notice the slector switch is in the safe position. one pic if with my finger of the trigger, and the other one pressing down the trigger completly with the lever still in safe.
http://imageshack.us/photo/my-images/823/photo1vqt.jpg
http://imageshack.us/photo/my-images/809/photohph.jpg