I voted "Other", though if there was no such option, I would have selected the LuciferBeam. I would submit that GTI managed to capture some examples of the Shivan beam weapons, completely intact, early in the great war, possibly even before the Ross 128 attack. They had examined the technology in great detail and were already working towards creating their own native beam weapons. This research would be recovered after the collapse of the GTI, and eventually go towards the development of beam weapons for the GTVA, towards FS2 era.
As non-rogue elements of GTI were beginning to uncover the rogue elements' plans, they decided that they would need the technology sooner rather than later. While they couldn't create their own beam weapons at this point, they went with an option of arming the Hades (which was basically completed and just awaiting the proper armament) with what Shivan beam weapons they had acquired. These beams would need Shivan power conduits and reactors (or whatever). in order to function properly. GTI had acquired some of these when they stole the beam weapons, but had to secure some more, which was part of the reason that they were conducting operations in Ross 128, which was a main Shivan staging area during the height of the great war, and contained
of Shivan supplies. With all these systems acquired and grafted into the Hades, it necessitated them to mount all-shivan weapons... no Terran weapons. For this reason, the electronics signatures of the ship showed up as Shivan.
As for the Hades' beam arragement, I vote that they only captured 3 working examples of the LuciferBeam, but also got some lighter beam weaponry, either AAA weapons or perhaps a slash-variant of the Luciferbeam, with dammage factors akin to the SRed, which occupy the other 2 beam emplacements.
Its a little involved and may conflict with your pre-established plotlines, but that's my take on it. Maybe I've deciphered YOUR plot.
Later!
