Koen van de Sande posted a message about Re: Secret tech level ??! in reply to Secret tech level ??!
> 1) After I change the tech level of some units, it works, but after few missions, they seem to disapear, and only units that can be on a level are on it, and no one else...
> Can a mission define what units are allowed ?
Yes, a mission can define that information. Most of the time they just set the TechLevel to -1 and you can't override that (because it's in the mission)
> 2) After a modification what exactly makes the game to re-read the rules ?
> (a) a new mission starting
Yes. At the start of a new mission, the rules.ini is read in (if you made your changes before the game)
> (b) a reload of a loaded mission
If you load a saved game, you have to restart the mission.
> (c) hope not, a new campain...
It works - but you don't have to.
Note that with all 3 options, you have to have your rules changes before you run the game.
> "No matter how obsessed you are about one thing there will be ALWAYS someone more obsessed then you !" 
Koen van de Sande
Van de Sande Productions
koen@tibed.net