Not just that, but did you expect a GM to come in and say, "Here. Here is the way to completely win the invasion. You just have to do these simple steps, and all the monsters and Daimons will be gone for good."?
Not at all, but on the other hand did you really expect the players to read your mind?
Any plot in an RPG, whether BM or table-top, needs to have appropriate plot hooks. If you go to the effort of developing a story element that your players can use, you usually also build in a hook for them to find out about it, assuming you ever expect them to actually be able to use it. You don't (and shouldn't) have to shove this hook in their face, but for the plot to be a good one there has to be a reasonable chance for your players to find it, otherwise what the hell is the point of putting it in there?
Now, it's entirely possible that there *were* hooks and we just never found them or recognized them, but you sure don't make it sound that way.
