[dnanian]

If you're doing this scheduled, Control-click the settings package in the Scheduled Copies folder (in Library/Application Support/SuperDuper!). Then edit the Copy Job.applescript you find in there. Add your commands to mount/unmount to the documented areas at the top of the script.

Save the script file, then go into SD! Uncheck and re-check the schedule checkbox (Edit the schedule). That'll re-compile the script for you, and you should be all set.