custom faction "rearrangement"

[fomalhaut]

I've read a few AAR's and seen some Post Your Empires and have seen some "custom" factions created by changing the info for x faction, or simply just changing the color for an existing one. Like using the slot for Epeiros to "create" (im trying to over use these as i know nothing is being created here, just data rearranged) an Massila faction or turning the Pahlavan from pink to a more neutral color.

How exactly would i do this? am i just making this up in my head? Which .txt files would i need to alter in order to, lets say, 'replace' Epeiros to instead be Syrakuse or Massila based faction? I really want to play as a Mediterannean Hellenic culture but not necessarily Epeiros, Koinon, or Makedon.

[Atraphoenix]

As far as ı remember you have to mod descr_sm_factions.txt file in data folder and for renaming a faction expanded_bi.txt and descr_strat.txt in text folder.