Hi,
consider – maybe in addition to Clones – Retrospect Desktop. When you tell it to run (automated) backups off your mounted encrypted image, it should be able to put only the changed part into a backup-file either on another HD or onto DVDs. Retrospect has pretty tough encryption as an option. The only problem would be that the catalog to read that growing file would grow as well and needs to be backed up for convenience (one can restore a catalog-file off the backup-file but that takes a huge amount of time).
Retrospect runs in Rosetta, so there is a slight but not too great speed-penalty if you run it during the day instead of during the night and donot want o keep you encrypted image open. If you run it as part of your shut-down-procedure that might work.
Rolf
PS: have a look at the latest TakeControl on Backups and the free online-primer on Retrospect at
http://www.takecontrolbooks.com/reso...etrospect.html