BI.exe custom battles

[TruePraetorian]

I've spent numerous hours trying to find the thread about BI.exe and enabling the custom battles, but they have slipped away to somewhere deep in the forums..

Can anyone refresh my memory on how to make custom battles work again? I'm actually running RTW as a mod folder, with my shortcut on BI being "C:\Program Files\The Creative Assembly\Rome - Total War\RomeTW-BI.exe" -mod:data -show_err", this is the way i've always played rtw with BI. I seem to have a vague remeberance of which files you must add to the folder to make custom battles work, something to do with the base folder?

Any help would be appreciated