I just wrote this little script to show the output of "iptables -t mangle -L -v" in the webif

put this in /www/cgi-bin/webif/QoS.sh

#!/usr/bin/webif-page
<?
. /usr/lib/webif/webif.sh

header "Status" "QoS Packets" "@TR<<QoS Packets>>"
?>
<table style="width: 90%; text-align: left;" border="0" cellpadding="2" cellspacing="2" align="center">
<tbody>
        <tr>
                <th><b>@TR<<QoS Packets|Quality Of Service Packet Info>></b></th>
        </tr>
        <tr>
                <td><pre><? iptables -t mangle -L -v ?></pre></td>
        </tr>
</tbody>
</table>
<? footer ?>
<!--
##WEBIF:name:Status:4:QoS Packets
-->

then chmod a+x it!