Open postbit or postbit legacy and search for
PHP Code:
<if condition="$post['signature']">
<!-- sig -->
<div>
__________________<br />
$post[signature]
</div>
<!-- / sig -->
</if>
Replace with
PHP Code:
<if condition="$thread[forumid] != 10">
<if condition="$post['signature']">
<!-- sig -->
<div>
__________________<br />
$post[signature]
</div>
<!-- / sig -->
</if>
</if>