As far as the school goes.... get a copy of their discipline police and go over it. The more you know, the better. I would also make it clear to your husband and the school that if this sort of situation comes up again that you are the only appropriate person when it comes to "parental notification".
As far as your daughter goes... it is so hard for any of use to understand what is going on with her. I was a mess when I was her age! And it wasn't anything I would talk to my parents about. Can you think of any adult she <I>would</I> talk to? When I was that age, there was a family friend who was in college and she really helped me out a lot. She was older, more mature, but not so old that I felt like she couldn't understand what I was going through. I too refused to see a therapist. When I was forced, I was a complete a$$!!!!
Another thing that seemed to work well for me, and still does, is letters. My dad would write me letters telling me how he felt, what he thought, and I would reply in a letter. It gave us both the time to think about what we were going to say and it avoided any sort of verbal screaming match. And of course, filling a letter with a ton of positive reinforcement helps. It would be good for you both to be able to express to one another that you recognize the good qualities each other have. You could phrase it like "I'm proud of you because....." "It makes me sad when...."
When I was in college I had a class about relationships and we practiced an effective form of communication that went something like this:
1. State the problem
2. Express what you sense about the problem
3. Tell what it is you are thinking about the problem
4. Tell how you feel about the problem
5. Tell what you want to happen about the problem
6. Tell of your intentions on how to solve the problem
The idea is, you go through each one of these steps, in that order, without the other person saying anything. Then, when you are done, they can do the same thing, or you can just discuss. It takes some practice to get it down, but when you do, it can be a extremely useful tool...not only for your daughter, but with everyone you come in contact with. Even if you can't get her to "participate", it's still good to do it on your own because it helps you understand and organize your thoughts.