In Confluence, the Pages rendered just removes all tables classes and styles and applies it's own:

<table class="confluenceTable">
<td class="confluenceTd">
....
....
</td>
</table>

 

To conquer/avoid this, use the jQuery AJS:

<div name=webfooter id=webfooter>
<table>
<tr>

......
......
</tr>
</table>
</div>

<script language=javascript>
jQuery(document).ready(function(){
    jQuery('#webfooter table').removeClass('confluenceTable');
    jQuery('#webfooter table').css("border","0px solid black");
    jQuery('#webfooter table').css("valign","top");
    jQuery('#webfooter td').removeClass('confluenceTd');
    jQuery('#webfooter td').css("border","0px solid black");
    jQuery('#webfooter td').css("vertical-align","top");
    jQuery('#webfooter td').css("padding","10px");
});
</script>

This enables You to do quite extensive manipulation, the main downside is that it's client based.