The [first pass] Mountain Lion update to the Encrypted Time Machine Backups on Time Capsule post: the script (mostly) works, as do the backups themselves (mostly).
Unfortunately, the script fails to properly detect the Wifi adapter’s Mac address (which I think has to do with changes to the output of system_profiler, something that should be fixable).
Mountain Lion makes visible changes to the process, namely, it will detect that the sparse bundle is present and encrypted:
It will furthermore ask and automagically remember both the TimeCapsule password and the encrypted disk image password. which means we no longer need to fiddle with Keychain Access:
But wait, I said “mostly”. It turns out Time Capsule will resize the sparse bundle image to (it seems) the size of the physical media hosting the image. While this can be changed back with hdiutil, I don’t yet know if Mountain Lion will simply resize it back in the next backup iteration.
Take some, lose some.