Hi george
As well as all the great suggestions made already you might want to have a look at our article on toilet training. Most of it will be things you've clearly already dealt with but there could be some tips in there that may help.
http://www.autism.org.uk/living-with-autism/understanding-behaviour/toilet-training.aspx
I hope you'll find something useful there. 
Sandra
Hi george
As well as all the great suggestions made already you might want to have a look at our article on toilet training. Most of it will be things you've clearly already dealt with but there could be some tips in there that may help.
http://www.autism.org.uk/living-with-autism/understanding-behaviour/toilet-training.aspx
I hope you'll find something useful there. 
Sandra