The scoop on activatePackage and deactivatePackage() ?

How you do use packages? I created a package that I am exec'ing enabling from the top of my mission file. I've tried putting deactivatePackage(MyPackage) in endGame() within the package, and outside the package and also tried to schedule it from both inside and outside the package but I cannot get it to unload.

Can someone show me an example of a package that can be loaded and activated from the top of a mission file and deactivated say, when the mission ends before the next mission that works with the current HEAD ?

Thank you,

Robert