Fix header of gridview with over 10 columns and scroll vertically

I have a gridview that is over 20 columns.  I am trying to get the header to not scrollable.  Below is my current code.  

<pre lang="vb">
<div id="divElementInfo" runat="server" style="width: 90%;">
            <div runat="server" style="width:900px;height:400px;overflow:auto">
                <asp:GridView ID="gvElementInfo" runat="server">
                    <AlternatingRowStyle BackColor="#CCCCCC" />                            
                    <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" Width="90px" />
                    <RowStyle HorizontalAlign="Center" VerticalAlign="Middle" Width="90px" />
                </asp:GridView>
            </div>
    </div>

I have tried all of the suggestions, but I haven't found anything for the vertical scroll.