Garrisoning buildings

[Aleksei]

So, I really like the garrison function in this game; I find it to be highly intuitive and yet intricate; given that you're able to select which windows and holes to fire out of, thus giving you a proper field of view and more to think about when arranging your troops.

However, I really don't understand at all how to garrison two-story buildings. On many occasions I'm playing a defense map and am given a gigantic two-story structure overlooking a critical defensive avenue that I would just love to fill up with a billion riflemen, but whenever I order them inside the roof doesn't disappear and I can't really see what I'm doing.

If I zoom in, I can sort of see inside, but I'm not given the ability to have my men set up at windows - the "ghosts" don't show up that indicate they're behind cover. I also can't seem to get them to go up stairs for the life of me.

Is there something I'm missing, or some sort of trick to this? It's really getting on my nerves.