Ok, so I figured out that the
OnClientAppointmentDataBound will allow me to make changes to the appointment i.e. back color. I also found a help topic that indicates that this is a more effiecent binding method because less html is moved due no postback
http://www.telerik.com/help/aspnet-ajax/scheduler-webservicebinding.html. This control has been a little more complex to work with then other Telerik controls but the functionality is very good.