Anyone know how to use the T setting on this combination? I just picked up an RB67 Pro-S on the cheap with the 180. I wanted to play around with doing some night shots with it, and I can't figure out for the life of me how to get the T setting to work- it opens the shutter and leaves it open, but it doesn't close on a second press of the cable release, whether it is hooked into the body or the lens release socket. Any suggestions would be greatly appreciated, as it is still under warranty.