Backing up with a shutted down computer

[titib]

Hello,

I'm dowing my backups during the night. So, I must to leave my computer on all night long.
In the User's guide, I've found a solution:

SuperDuper! does not have to be running for a schedule backup to
take place, but the user who scheduled it does have to be logged in,
with their account in front (if Fast User Switching is active), and the
screen must be unlocked.
If your Macintosh is asleep when the time comes to run the backup,
SuperDuper!’s scheduling won’t wake it up, so the backup won’t run.
The way to handle this is to use the Energy Saver Preference Pane in
System Preferences to schedule a wake (or “start up”) event for a
minute before the backup is scheduled to run.

The problem is the next one: I've got many users on this computer, then, when my mac wake it up, I have to entry my login and password (but I can't - because I'm alseep ), and then, SuperDuper can't do the backup...

Do you have a solution?

Thank's.

titib.