Mine bites scratches pinches non verbal and its when she doesn't get what she wants. Mine is so much younger so I doubt i am of any help but interested in what others might have to say. I did buy her teething sensory necklaces so she could bite those when angry which didn't really work for me. I either plan that she is going to have a melt down so have something to distract right away or I will grab her by the shoulders (so she's not near me lol) and do some hard massages and joint compressions and it settles her down asap. Not sure if that will work when she's older. I still see her jaw after people but those people have learned to be quick (or else). Again she's small even though she's busted my teeth a few times.
When I went to autism training classes the one major thing they said over and over is you cannot punish an autistic child. They don't get it. They won't get it. They don't relate the two things at all. You give them limited options and limited questions. You have to tell them how it's going to be in other words.
There was a grandma there who desperately wanted to punish the child with no bed time movie if he hadn't cleaned his area and the teachers were begging her NOT to do that. that it wouldn't work (and it wasn't). It was and is a hard concept for mainstream people to understand. Autistic kids are just on a different playing field and you have to learn how to get in there and figure it out.
My dd now tries to bite the floor which is better but still weird and will only bite you if really pissed. She needs a lot of compression and massage. I noticed if she has 10 minutes of say body massage or swinging by the arms (joint compression) then she is awesome for quite a long while. She will actually go out and seek these things herself like bouncing her tummy against the couch or wadding a blanket up and rocking her tummy on it with her legs indian style.
I think this is the book we had in school http://www.amazon.com/Teaching-Social-Communication-Children-Autism/dp/1606234420/ref=sr_1_3?ie=UTF8&qid=1308895546&sr=8-3
It's a tough tough road. We also had a mini weighted vest (so adorable! as she is not only two but very petite and the smallest size was too big almost and those itty bitty weights lol.). I also find people specifically trained in autism "get it" more than speech and OT people who work with everybody.
And btw biting back does NOT help. I was getting hurt THAT bad and did it and all it did was make me feel like sht and realize she has a super high pain tolerance and couldn't give a rat's behind what I did. Again autistic kids don't relate the same way.
It's like an alien teaching you how to write alienese with an alien pen and you have no idea that's what they are doing in the first place or even trying to get you to do and you can't see the ink. It doesn't make sense and it's not going to that way. It's just not the same as an ehhh "easier" child.
I hope you get some good advice and I can steal it as I am sure I will be having these same problems.
Oh I also pet her face. She likes that and she closes her eyes like it's raining marshmellows on her. Just an accidental discovery lol. Not as good as massage but does calm her down.