There's a mod that adds the campaigns from the original game and "Hammers of Fate" to "Tribes of the East." You can download it on Hugo's Corner. Search through the list of mods, and you'll find it. There are also many threads dedicated to this mod. As for me, I can say that it's very buggy: locations disappear in the cutscenes, some scripts are broken in the game, and assembled artifacts don't carry over to other missions. It seems to me that it's better without this mod ;). Moreover, to remove it, you need to reinstall the game :(.