I have been excited about Lion allowing full disk encryption of external drives. I have a usb hard drive connected to my Airport Extreme which I use for Time Machine backups. Since this is an easily stolen item, I really want it encrypted. However, I can't figure out how to enable encryption on this in lion. It seem that the "encrypt this drive" option in Time Machine doesn't allow you to use it on a network drive. Also the FileVault prefs pane won't show the network drive (only my local drive). Am I missing something?!