I figured I would have to use bulb but I was wondering if there was another way to keep the shutter open for an indefinite amount of time using live view.
I am still waiting to hear back from Sinar to see if they have any documentation about using any of the Precision backs with the cameras they support in the software. The set up is not as obvious as some may think, especially if you are not use to MF at all.
Unfortunately there is no M11 manual only the manual for CapturePro so I am not really sure what else to do. In the meantime I will keep trying different settings and see what I come up with.
I think you would have to use bulb for the LV. That's what I have to do with my Contax, with a cable release.
Can't help you with your other problem because I've never used a Mamiya. Maybe you need the winder cable too. Is there a shutter speed slider in the software when you select Mamiya AFD as the camera? When I used that back with a Fuji 680 I had to tell the software the shutter speed I had set on the camera otherwise there were weird timing issues and streaking on the image.
Ben