[dnanian]

Dave:

The scheduled backup scripts have a way for you to change them, and add commands before and after backups: using that, you can mount/unmount volumes at will.

You can also use the "On successful completion" script to unmount, should you wish to.

At present, though, v2.0 won't have a formal UI for mounting/unmounting volumes: in our experience, this isn't something that people make mistakes with (although, of course, they could)... but, should it prove problematic in a significant way, we'll take steps to address it for all users.