Hi I teach kindergarten and I currently have a child with autism and a child with aspergers in my class. I use the 5 minute time out with a visual timer so the child can see how long the time will be and how much time is remaining. I place a chair in a place where I can still see the child and we use this as out time out chair. I also remove privileges when needed but also use positive reinforcement, encouragement, and rewards that the child would be interested in when he/she does something correctly. For example, putting sneakers on by themselves, completing work on time, playing or behaving correctly in social situations and play time..etc. I would recommend being consistent, calm and firm with the time out, also choose just one thing at a time as a focus behaviour, and gradually work in more as you move along. For children who suffer from autism  and aspergers the world can seem very  overwhelming so take it slow and be patient.

Good Luck!

Its best to talk with parent and encourage them to maintain a behaviour chart at home.It's difficult to maintain a consistency without home support.You could also try using Home-School behavior management sheet.