Unfortunately I can't be too helpful on this one, other than to say, that a recent training course that I attended, suggested that children with this disorder need time to 'chill' out, and it was suggested that they be sat in a green room (I don't mean plants) I actually mean a room painted green, as apparently the color green is the most relaxing to the mind/eye. If this can't be achieved it was suggested at school that maybe sitting near the window helps to 'mellow' the child out.
Even overlooking green grass through a window is supposed to help.
I haven't tried the suggestions out, but seeing that it wouldn't cost anything to try, I would suggest it may be worth a shot, at any rate, it wouldn't hurt to try.