Hey there.

I have the switch you used and the washer with the funny looking right angle metal bit is suppose to go behind the face plate. If you look at the center where the switch passes through, you will see it has a 'finger' that goes into the grove of the switch. Soooooo when it is on the other side and facing the other way, that little metal thing at the top presses on the top of the red box behind the switch to stop movement.

I know I suck at explaining it but I thought I would try to explain it XD. I don't think it's going to make that much of a difference anyway.