He made an extra homie slot for the mech suit in the homies.xtbl file, but instead of it putting you in the mech suit, it replaces the protagonist's body with that of whatever NPC it is assigned to, which was Maero in the pic that he displayed. I believe he has the file attached in a separate forum under Mod Releases, but I'm not quite sure exactly where it is. Once you get it, though, you can replace the mech suit with Killbane, seeing as his model is in the game's files.