The Black Soul Gem ability is hard-coded and can't be given to anything else. You might be able to simulate it using OBSE. You would probably need to use http://cs.elderscrolls.com/constwiki/index.php/GetSoulLevel to determine the soul and then use RemoveItemNS to remove the empty "Balok's Star" and AddItemNS to replace it with a "Balok's Star" with the appropriate soul level.
yeah, that's kind of what I figured after looking for anything I could find that governed it and not finding anything. No biggie, it was just an idea I had on a whim, lol.
Just out of curiosity, would the First Federation really leave an artifact that powerful just laying around on such a primitive world?

Definitely not, however, it appears that one of my subordinates had too much Tranya on one of their "adventures" to a new planet they discovered, and they umm,"misplaced" a few, lol!