If the principal, main teacher, and counselor are able to convey specific strategies for teaching your DS to the PE teacher in a form she'll accept, that may be the best way-- you know the culture of your school. Teachers in general hate being told how to teach, so hearing it from a peer can be better for them than hearing it from a parent.
On the other hand, if you think you'll be working with her for years, the more you can build a relationship with this PE teacher, the better.
Hard stuff.
DeeDee
I think the Montessori teachers generally really respect the school psychologist's opinions with situations like this. I am thinking of asking for a meeting with the PE teacher and school psych (aka guidance counselor-she is a licensed school psych though). The private counselor will probably have some good ideas too.
The thing is, the best ideas are the ones that require a teacher to alter her teaching style. I'd prefer to find a solution that requires little effort on the teacher's part because I think we'll get more follow-through.
I love the idea of allowing ds to be more of a helper. He really responds to this kind of thing, but is that fair to the other kids? I don't think so, and ds would probably feel strange about having a role that no one else gets. He doesn't want to stand out as different, yet that's exactly what's happening when he has a meltdown.
Hopefully, if all goes well, ds will be at this school for another 3-4 years. I do want to get to know the PE teacher better and establish a good rapport. We'll get a lot more mileage out of this method, I'm sure.