Damn I thought after two years, there would be SOME answer, but I guess I can try again, better to use a old topic then start a new one with the same question
Hmm, the people who would know the answer to that are unfortunately no longer active. I think (and I have no coding experience) that stuff is probably hard-coded, though. You could try sending a message/email to Daxter. He was the lead for OGaM and knows a LOT about the code for BW2.
sadly coding for B&W2 and botg is different. For botg lionhead made a few changes to the way you script the land.
You could try playing around with the Balance Files. Its likely that there is a setting in there for the time the army lives for.
Even if we could change the code, we would need to get the source code, then recompile it for botg scripting language.
To be honest in general people who like modding games, I am one, do it not for just themselves but for a wider audience. As a game ages we tend to move on to new games, I never got into modding B&W2/BOTG simply because I was doing mods on other games.
Why am I still here..... I don't know perhaps just "Waiting for Godotus.
As with many of us, the real world got in the way of our projects/hobbies. If I recall correctly, Dax had some computer issues and lost a lot of his coding work. Very few people play BW2 anymore, so demand wasn't there either. And then there were issues with hardcoded parts of the game that were a pain to deal with. Basically a lot of stuff all came together at the worst time and the project fell through.