Ok guys, I did some testing with PigTones voice files and decided to share my observations.
I am using nuvi 40lm and Win7x64

1. Voice Editor will crash if the voice is encrypted. For example try opening darth vader or yoda garmin voices.
2. Voices that are not encrypted will only show up on the device if the language ID changed to language you currently don't have on the device.
This means that instead of the name "Pigtones Arnold.vpm" you will see the name of the language, ex: Chinese.
3. The encrypted vpm files will show up with a proper name on your device. Some of the Pigtones vpm files were encrypted and show up just fine.

Why do encrypted files show up with normal names on garmin?
Do these files use language ID and if not, what are they using to be identified by garmin?