Mapping problem.....content dependent on response

Hi,

I've got a mapping as follows

Part_ID (context = report) \

Datarow (context = report) - UseOneAsMany --> Check_Part_ID (my UDF) ---> IF THEN Datarow -

> Recordset

Datarow (context =page) /

A request for a report is sent and if a report is found

 
<REPORT>
   <REPORT_HEADER>
      <HEADROW num="1">
         *<Part_ID>PT_500024</Part_ID>*
      </HEADROW>
   </REPORT_HEADER>
<REPORT_BODY>
<PAGE>
   *<DATAROW num="1">*
      <TRADE_DATE>17/01/2008</TRADE_DATE>
   *</DATAROW>*

This maps fine. The problem is that when no report is found the reponse is

<REPORT>
   <REPORT_HEADER>
      <HEADROW num="1">
         <REPORT_NAME>Report</REPORT_NAME>
      </HEADROW>
   </REPORT_HEADER>
<REPORT_BODY>
    *<NoDataFound/>*
</REPORT_BODY>
</REPORT>

My mapping throws an error as Datarow and Part_ID don't exist in this response. Is there anyway I can solve this by using the <NoDataFound> tag in the second response