That's strange... although I haven't tried to create a custom faction since a while ago (probably before the beta), I can still use my custom faction from before, as I have been doing. So if you want to create a custom faction, you may be able to mod one to make what you want just through the xml stuff. If you need more info on modding, you can either check the modding section, or I can elaborate if you wish, just let me know 
