数据重新加载后，WPF Toolkit DataGridColumnHeader不维护Style

I am using Toolkit DataGrid. There is a custom header style when user sorts any column. But the data is refreshed after every few seconds and the new datatable is retrived from the server(I made the data in datatable sort based on the original sort).But because of this the header goes back to the default look. I have tried explicitly assigning the sortDirection on the column like...I am using Toolkit DataGrid. There is a custom