[Nitram Draw]

WH,
You don't edit the .emp files. They are created when you save a race. I think they contain the various points used, traits, culture etc. They can contain Minister settings for example and even ship designs used by the race.
I don't know if you remember but before patch 3, I think, not all the standard races could be manually chosen to add to a game but if they were chosen and you took control of them and saved the race you could then manually add them to a game.
I think the Pirate trait can be added, any trait for that matter, but its just that the info stored in the existing race .emp files won't have the new trait and therefore won't be available until you save the race during a game where the trait has been added to the Racial Trait file.