Update tabpanel header template

Hi

I am using a tab container with 8 tab panels inside, each containing an update panel. Each of the panels contains a form and I would like to display an image on the tab to indicate successful completion of the form. I have the following header template inside each of the tab panels...

<HeaderTemplate>
<table>
<tr>
<td><asp:Label ID="tab2Title" runat="server">2. Basic Information</asp:Label></td>
<td><asp:Image ID="tab2StatusImage" runat="server" ImageUrl="~/Images/tick_circle.png" Height="20px" Width="20px" Visible="false" /></td>
</tr>
</table>
</HeaderTemplate>

I thought it would be a simple case of making the image above visible in code behind using tab2StatusImage.Visible = true in code behind but this does not work for me.

Anyone able to point me in the right direction?

Thanks!