The more you understand them the easier it will be to work with them. I see so many people just give up, because it's too hard or they just don't have the patience. Don't give up!! And I agree that mainstreaming the children is always the best thing to do if you can. These children are seperated enough in life from "normal", people they shouldn't feel different or seperate in the House Of God. If your having problems in the class room with the children ask the parents to come and show you how to handle them better during class time. We can learn a lot from the parents, they are the real experts!!
Remember also to minister to the parents. They need as much support as you can give them.