Scrollable GridView with Fixed Headers Header Column Alignment in ASP.Net

Scrollable GridView with Fixed Headers inside ASP.Net UpdatePanel using jQuery Plugin This post helps me alot Thank you so much. I have one more question in that.  How to adjust the width of the columns headers because for some of my gridviews the headers not showing the proper format.  in the gridview I gave HorizontalAlign="Left" and in the columns I gave 

<asp:BoundField DataField="XXX" HeaderText="XXX" ItemStyle-Width="150px" HeaderStyle-HorizontalAlign="Left" />  it's not showing in the correct formart. header is coming to the left side and data is coming to the right side