Versuch es mal so
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr valign="top">
<td width="20%">test</td>
<td width="80%" rowspan="2">Text</td>
</tr>
<tr valign="top">
<td>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td height="200" valign="top">text</td>
</tr>
</table></td>
</tr>
</table>