Didn't work at first for me.
I installed Rom Manager (premium)
Installed CW recovery
Tried to backup from within Rom Manager
I got a "Can't find update.zip" message.
When I rebooted and opened Rom Manager again, I got the "Error Occured" message, but it locked up on me and became unresponsive.
I uninstalled Rom Manager, rebooted, then reinstalled. I flashed CW recovery again, rebooted normally, opened rom manager again, and flashed CW recovery again.
After that I was able to use rom manager to reboot into recovery and backup.
Not sure if mine was just a fluke or what, but I figured I would share.
Galaxy Tab 7