How do you make a blacked-out scenario?

[unmerged(64071)]

In essence, I'm curious as to how one would go about making a scenario like the D-Day or Battle of the Bulge scenarios where certain territories are blacked out and the player can only view a limited area.

I'm going to be making a Mexico VS. Texas modern day mod but I want to keep it to just Mexico, greater Texas and the Carribean.

Any help is appreciated!

 

[unmerged(58571)]

You have to assign map data in the scenario definition.
First set yes or no (PTI) for all, then for each province that should have a non-default behaviour.
I recommend having a look at existing battle scenarios if this seems confusing.