Xcode 3.0 Snapshots: Notes on Repository Location

Man, I love this new feature. Being able to diff files to any of my previous Snapshots is superb. Being able to roll back changes on a single file or over the entire project is even better. I find I give myself more freedom to try new things because I know I have a good clean (compiling) Snapshot to fall back to. Scotty's Xcode Quick Tip is a great place to learn more about them.
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I wanted to make sure that I was backing up the Xcode snapshot sparse image, so I went looking for it. Currently, Apple's docs say the file should be here:
~/Library/Application\ Support/Apple/Developer Tools/Snapshot Repository

Well, the location in the current documentation is wrong, the disk image really is here:
~/Library/Application\ Support/Developer/Shared

I've also found that the defaults command for changing the location of this magical disk image doesn't work for me on Xcode 3.0. Anybody have any tips?
defaults write com.apple.Xcode XCSnapshotRepositoryPath /Volumes/Backup/Xcode\ Snapshots/