This is a recycled post but I sometimes have a hard time finding stuff. Elliot blazed a trail of sorts figuring out how to get a Rev drive to be useful with SBS backup. You need to load the Ev drive software and reboot the server. You need to run the SBS backup wizard.
Here is the copy Susan has on her blog.
While Iomega won’t go on record as supporting them, SBS MVPer Eliot has tested them and they will work…..
More information on the REV drives can be found here.
The Backup Wizard won’t write to REV drives b/c IOmega setthem to look like CDs, and the Wizard looks at whatever that attribute
is. NT Backup looks at the drive just fine, though. Since the Wiz
actually configures NT Backup, the best workaround to allow
you to use the Rev with the Wizard is:
Use the wizard to configure the backup to a hard drive, then open up
HKLM\software\microsoft\smallbusinessserver\backup and change the key
“Backup Location Path” to the Rev Drive.
There are some more comments at the original post.