The Act - Now (Autism Consultation & Training Now) website is a great place to go to find evidence based information on how to teach children with autism spectrum disorder (ASD) .
I have just been chatting to a colleague about how to toilet train a student with ASD and co-morbid intellectual disability (ID). The ACT- Now site has a terrific fact sheet download on the topic, that I have found to be very useful to refer to when working with children in my own practice.
Another very useful resource is the booklet '1 Step at a Time - A parents guide to toilet skills for children with special needs. This resource has been produced by the Victorian Continence Resource Centre and can be downloaded from their site.