After doing a bit of historical reading I discovered that the province of Cambray should belong to the Bisophric of Cambrai for much of the game and after seeing that Tiax had created some of the basics required, for his 1100AD mod, I shamelessly borrowed the files I needed and heavily modified them. I edited the map to make Cambray more accurate in size and changed the culture of the province to Wallonian to reflect the direction it looked.
I made one further change based on my historical discoveries and that was to give the province of Valenciennes to Hainault until that nation becomes part of Burgundy.
It was ponted out that I made an error in the history which has now been fixed. Cambrai is now playable between 1399 and 1543 where it is annexed by Spain. France takes it in 1678.