How do I access a textbox in the footer of a gridview?

Question

I have a .NET 4.0 web app and must be missing something obvious. I have a standard gridview with 1 column and a footer row. The footer has only 1 text box and 1 button so users can enter comments and submit them. However, I can't seem to reach the textbox.

Here is the vb code...

Dim strComments As String = CType(gvLog.FooterRow.FindControl("txtComments"), TextBox).Text

And here is the footer code.

          <FooterTemplate>
              <asp:TextBox ID="txtComments" runat="server" Height="59px" Width="530px"></asp:TextBox>
       <br />
        <asp:LinkButton ID="LinkButton2" runat="server" onclick="LinkButton2_Click">LinkButton</asp:LinkButton>
       </FooterTemplate>