I don't know to much about this file packer beacuse i have pro and i never use this. But did you talking about 3dgs tool or some other 3rd software?
This what you explained sounds like MoleBox or Enigma Virtual Box, BoxedApp Packer,... there are really a lot packer on market, but it is not free. I've been here for a long time but i have not heard that there is too much 3dgs packers. I only know for one from "Lion Toys", but that was long, long time ago.