Thank you for writing.
Your question has already been answered in the other thread you've opened. However in order the community to benefit I am copying the answer here:
Currently this is not supported by RadScheduler. We have a feature request for functionality that will allow you to choose the first day of the week. The feature request is logged in our Feedback Portal. You can track the item for status changes and add your vote for it here.
I hope this will be useful.