Can "Encryption Desktop" encrypt Mac OS formatted external drives?

Hello Symantec community!

I can't get a straightforward answer anywhere and hope someone here might have the answer.

I have several Thunderbolt external hard drives, all formatted Mac OS Journaled. The machine I'm on is a Mac Pro 6,1 running Yosemite. I installed the trialware of Encryption Desktop, but the only drives listed were the internal drives.

Did I do/configure something wrong? Am I using the wrong software?

Has anyone successfully encrypted an external Mac OS hard drive? I would go the FileVault route but the loss in disk speed (as minimal as it is) hinders video editing.

Best,

Jerome