[SuperDoper!]

I use SuperDuper! to backup a Mac mini Server with 2 volumes (BOOT, DATA) to a single external firewire drive with corresponding volumes (BOOT-BACKUP, DATA-BACKUP).

Now to make things simple and easy for the customer I've setup SuperDuper! to run a scheduled backup of each volume whenever the external drive is plugged in and these backup volumes are mounted; I have it run a script that sends an email when the backup of volume 1 (BOOT) is started and another email when the backup of volume 2 (DATA) is completed (and have SuperDuper! eject the drive at the end) so they know when they can safely unplug the backup drive and take it to a safe place.

Here is the problem: SuperDuper! does not always run the backup of the BOOT volume before the backup of the DATA volume but sometimes the other way round, so my "Backup finished" email arrives first (in the middle of the backup process) followed by the "Backup started" email, and ofcourse the backup process still takes a while to finish and the customer cannot tell when it is safe to unplug the drive.

So my question: How can I make sure my two backups always run in the "right" order?

Thanks,
SuDo