My personal feeling is that it wouldn't hurt to make the class diagram overly complicated, because if you look at Sun's grading criteria, 75% of the grade is addressing requirements, and only 25% is for UML compliance. They don't seem to be taking points off for having TOO MUCH stuff in the diagrams.
When I did the assignment, I noted this, and knew that my diagrams were very basic, but I wasn't worried about it, because I had a bunch more ideas for things that I could add if I got a failing grade. I was quite sure I would pass with what I already had, though.
Still, I think that having JSP's in the class diagram would be a bit much. Just my personal opinion.