Just make it a table, something like this:
Code:
<table border='0' cellspacing='0' cellpadding='0' width='100%' align='center'>
<tr>
<td background='graphics_to_display_befor_topbar.gif' align='top' valign='top'><img width='1' height='1' src='transparent.gif'></td>
<td background='graphics_to_display_under_topbar.gif' align='center' valign='center'><img src='what_ever_buttons.gif'></td>
<td background='graphics_to_display_after_topbar.gif' align='top' valign='top'><img width='1' height='1' src='transparent.gif'></td>
</tr>
</table>
Make sure the <td> and </td> is placed in connection with the <img> tag, else IE will repeat the transparent image, which in combination with specific height on the navbar might make it look srewey.