Kevin, composer does not support configurations. Basically, because it doesn't need to. I recommend that whatever configuration of the assembly you put it, make sure it has all the components you need just hidden, not suppress (in SolidWorks lingo). Then you can use Composer to make different views with those components that you need hidden or shown (think of kinda like a display state). Now if you are talking about configurations of components inside an assembly, you will have to go a bit further to get that. What I tend to do is bring that component config in seperately, then move it into place using it's similar actor for alignments. It is very fast once you can wrap your brain around it. Remember, Composer is not a CAD package so you need to think differently.