Hi Brette,
Sorry to be throwing more information at you - and others may disagree - but my peronsal experience is that I had no idea what sensory integration problems my DS has. I know there are hundreds of theories about ASD, and hundreds of people selling cures etc, but if you can afford it I would highly recommend getting an assesment at the sound learning centre. This showed us that my DS had distorted and hypersensitve hearing and visual perception problems. We did their recommended treatment (not at all cheap), and my DS went from walking out of class 5 times a day - to not walking out at all, and only having about 2 very mild 'incidents' a week. So it has been a huge and dramatic turnaround for us. And means that he can now participate in the classroom.
I am more and more convinced that a large number of his problems are caused by sensory integration problems - ie I believe that if he didn't have sensory integration problems he wouldn't have Aspergers.
Now, this is only my perosnal experience, and it is quite expensive. So maybe file this idea away in your 'good ideas' pile, and revisit it later if your son is having problems at school. But I was really really shocked to find out at age 9 how bad his vision and hearing was. I had no idea at all.
In terms of your OP about what school should be doing for him, I agree with pretty much what everyone else has. But I can tell you what support my son has had. He always has a TA in his class (I think this is normal for KS1, but isn't for KS2), he's had loads of anger management sessions, he's also had social stories (I think), and he's currently in a lunchtime club which offeres 'structured activites' for him and the handful of other kids who need it.
The lunchtime club has been invaluable. Because lunchtimes are a real problem for him.
Plus he's had some occupational therapy, including 4 sessions of sensory integration training, which again have made a noticable difference to him.
The outside specialists the school have consulted over the years are: The ASD Team, Occupational Therapist, Educational Psychologist and Behaviour Support Therapist.