[Lynne]

you would have to edit the templates posticons and posticonbit to change it. I think your would edit the following stuff in red...
posticons:

<table cellpadding="0" cellspacing="$stylevar[cellspacing]" border="0" width="95%">
            <tr>
                <td colspan="15"><div style="margin-bottom:$stylevar[formspacer]px">$vbphrase[may_choose_icon_for_message]:</div></td>
            </tr>
            <tr>
                <td width="12%" nowrap="nowrap"><label for="rb_iconid_0"><input type="radio" name="iconid" value="0" id="rb_iconid_0" tabindex="1" onclick="swap_posticon(null)" $iconchecked />$vbphrase[no_icon] &nbsp; &nbsp;</label></td>
                $posticonbits
                <if condition="$show['addedspan']"><td colspan="$remainingspan">&nbsp;</td></if>
            </tr>
            </table>

And in posticonbit:

<td width="12%">