Hi, this is my version with very very few modifications :
Code:
<table class="tborder" width="100%" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0">
<if condition="$post['signature']">
<tr>
<td width="175" class="alt2">
</td>
<td class="alt2">
<!-- sig -->
<div>
$post[signature]
</div>
<!-- / sig -->
</td>
</tr>
</if>
</table>
I put an already existent class so no need to add an extra CSS part.