RadPivotGrid will always apply sorting on your data. But there is a way to achieve the desired order - you can create your own object and implement IComparable. When RadPivotGrid tries to sort your data, it will use your code, so you can add a sort key or something more meaningful for your case, and sort the data as you wish. I'm sending you a simple project demonstrating how to achieve this. Please take a look at it and inform us if you have any problems or concerns.
the Telerik team