Yes, this can be done by setting the FirstDayOfWeek property to the day you wish to start the week from. We found out that this is not working in XAML with the latest official distribution of our controls. You can set it only in the code behind. We fixed it and the fix will be included in our next release (at the end of February). If you need it earlier, please write to us and we will send you a hot fix.
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