in your demo here http://demos.telerik.com/aspnet-ajax/scheduler/examples/overview/defaultcs.aspx
you can add a weekly event of say mon, thur, sat
and it shows correctly. the code seems to be built into your dll or something. I don't see how you are adding the WeeklyRecurrenceRule.
it seems the appointment can only have 1 rule and the mask for the RecurrenceDay only has single days, weekdays, weekenddays, or everyday.
how do you add a mask of mon, thur, sat?