New factions - banners and icons?

[Midnight]

Can anyone tell me what the files I need to edit to create new faction banners and icons, and to change the names of the factions are?

I have something planned, but it just doesn't look right having my men running around under the Seleucid banner, and belonging to the Seleucid faction!

I had the banner information bookmarked from topic over at twcentre, but I can't access that at the moment.

Any help would be appreciated.