Sorting order get changes when I assign to response object.

Hi, I have a list which I have sorted based on legal event date and then assigned to a object(HighAlertDisplay domain object). When I try to assign the sorted object to the main response object(GetBusinessResponse), the iteration value get changes. I know I can achieve from UI. But I need this to be achieved from MF as in HightValueAlert have mutiple  values from different source.