You can edit
function postResponse($msgid,$response,$signature='none',$attachment=false,$canalert=true)
in class.ticket.php here
',response='.db_input(Format:($response)).
line 716
then you need to go to staff/viewticket.inc.php and edit
<tr class="header">
<td><?=$ticket->getAttachmentStr($respID,'R')?></td></tr>
<?}?>
<tr><td> <?=Format:($resp_row)?></td></tr>
</table>
into:
<tr class="header">
<td><?=$ticket->getAttachmentStr($respID,'R')?></td></tr>
<?}?>
<tr><td> <?=$resp_row?></td></tr>
</table>
and there u have it. Html body msg. :)