Auto-run an app/shortcut when a disk is connected?

I just got a WD My Passport Essential but I'm not too fancy about their SmartWare software. It seems buggy and really unnecessary, when the only thing I want is the password protection (encryption) built-in to the drive.

Unfortunately, when I connect the drive, I have to click on the virtual CD that then mounts and then launch "DriveUnlock" app to enter my password. I had hoped it would integrate with OS X better. Once password is entered, the disk will mount my drives.

Anyway, is there a way I can get OS X to run that DriveUnlock app by itself when it sees the disk being connected? I doesn't help to make it run when the drives are mounted since they don't mount until after password is entered.

Thanks.

 

I've looked at Automator but I don't see any actions that would be triggered by a (virtual) CD being mounted.

Any idea what it might be called?