You will not be able to achieve the exact scenario as by design SpecialSlots do not provide selection, but you could have similar behavior by making some changes in your current setup.
First, you will need to get the SelectedSlot and according to its Start and End times search inside the SpecialSlots collection and find the corresponding SpecialSlot. This, however, means that you should set the MinorTickLendth property in such a way that both regular and special slots are comparable.
I hope this will help.
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