Adding a new race

I've been trying to add a new race to Sins and while the units (or the one's I've tried) all seem to work with the other races, when I try playing as my new race, I don't get a construction frigate or a frigate factory. Searching through the forums seems to reveal quite a few threads about it, but all are several years old and involve modifying the GalaxyScenarioDef file, one which I don't seem to able to find in the Diplomacy GameInfo folder. Any advice on what to change to fix this matter would be greatly appreciated.