Is it possible to add a new faction?

[Shaka_Khan]

I would like to add a new faction without erasing the MTW VI ones. How do I add factions in Viking and Early Era? I'm not thinking of adding any in campaigns. I'm going to add them in the custom battle area. I noticed that there are a lot of stats and other things to change. Is there a way to have a new faction and play the older ones online?

edit- I found the guide on the other thread. Do I need to add sound? And is there a program that adds a new faction?

edit2- I got a 'COLUMN_unit_type' message. It said,

"Unknown unit type encountered
column 2, row 183

STW_AshixBow"

What am I missing?