I have a 2TB Western Digital portable external HDD that I have partitioned twice - one partition for miscellaneous media and the other for Time Machine backups. I'm able to encrypt the partition with the media through Finder with no issues but I don't have the option to encrypt the partition the backups are on. When I go to the Time Machine preference pane, the option to encrypt the partition is grayed out. Any ideas? I have FileVault 2 enabled on my MBP and it seems redundant to have it enabled if all of the data is just being backed up to a drive that is readable by another computer with no encryption.