With the expansion startpos files, the lines look like this (exact copy/paste here):
Code:
SetFactionCol:: FN_ALMOHAD  			255 138 0		32 32 32
You would need 2 sets of numbers, major and minor. The Danish line looks like this:
Code:
SetFactionCol:: FN_DANISH				255 255 255		255 0 0
which gives the white/red combo.

But if the lines weren't in your EARLY.txt, the colors are probably specified elsewhere and adding them will make the parser fail on the file when the game comes up. There are v1 compatible mods out there that added factions, so I'm sure there is a way to do it.