Traversing returned HTML

Traversing returned HTML

HI all,
I have a form that submits to a third party WCF service. When the form submits it returns html. Based on that html I need my ajax submit to fire a success function according to the reply. The reply is as such:
<HTML>
 <BODY>
 <TABLE border='1'>
 <TR>
 <TD><b>Field Name</b></TD>
 <TD><b>Field Value</b></TD>
 </TR>
 <TR>







 <TD>SuccessFlag</TD>
 <TD>TRUE</TD>
 </TR>
 <TR>
 <TD>ResponseMessage</TD>
 <TD>Service Cancelled</TD>
 </TR>
 </TABLE





>
 </BODY>
</HTML>

how would I write a success function if the SuccessFlag returns a TRUE in that td? I have tried
success: function(data) {
      var useTD = $(data).find('table').children('tbody tr td:nth(4)');
      if (useTD == 1) {
      $("#request").remove();
                         $("#requestSuccess").fadeIn("slow");
                    } else {
                        $("#request").remove();
                         $("#requestError").fadeIn("slow");
                    }

to no avail. I have also tried using the :contains but I can't get that right either. Im sure someone knows a better way! Help a designer out!
Thanks,
Kane