Gridview - Query Regarding The Nested Grid Views In C#

I have defined a nested grid view in the following way.

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataSourceID="SqlDataSource1" OnRowDataBound="GridView1_RowDataBound" GridLines="None">
<Columns>
<asp:BoundField DataField="Date Of Transaction" HeaderText="Date Of Transaction"
SortExpression="Date Of Transaction" />
<asp:BoundField DataField="Invoice Number" HeaderText="Invoice Number" SortExpression="Invoice Number" />
<asp:BoundField DataField="totalAmount" HeaderText="totalAmount" ReadOnly="True"
SortExpression="totalAmount" />
<asp:TemplateField>
<ItemTemplate>
<asp:GridView ID="gridView2" runat="server" HorizontalAlign="Left" ShowHeader="false" GridLines="None" OnRowDataBound="gridView2_RowDataBound">
<Columns>
<asp:TemplateField ItemStyle-HorizontalAlign="Center" ItemStyle-Width="100px">
<ItemTemplate>
<asp:Button ID="Btn1" runat="server" Text="Download" OnClick="Btn1_Click"/>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ComponentDBConnectionString %>"
SelectCommand="SelectUserPreviousHistory" SelectCommandType="StoredProcedure">
<SelectParameters>
<asp:Parameter DefaultValue="XYZZ" Name="userName" Type="String" />
</SelectParameters>
</asp:SqlDataSource>

The screenshot of the output is here. As you can see i have a "Download" button in each row of the child gridview (i.e., gridView2) but I want the download button to be last column but .net is rendering it to be the first column. How can I do it? More over gridview2 datasource is arraylist. Here is the code

gridView2.DataSource = titlesArrayList;
gridView2.DataBind();