Reporting Services :: Exporting SSRS To XML Format

I need to generate a  report in XML format . Expected XML format is 

    <?xml version="1.0" encoding="UTF-8"?>
    <ns:SPO xmlns:ns="urn:abc:SparePartOrder">
    <SPOrecset>
<SPOK>
<ZCODE>O</ZCODE>
<KNDNR>00009999</KNDNR>

[Code] ....

I have tried two methods to get the above XML format.

1. Modified  XML Nodes - Created a stored procedure which returns the required informations from database. To get the XML format I have modified  XML Nodes using  DataElementName property from SSRS. I have added the
following code in rsreportserver.

           <Extension Name="Custom XML"   Type="Microsoft.ReportingServices.Rendering.DataRenderer.XmlDataReport,Microsoft.ReportingServices.DataRendering">
           <OverrideNames>
                           <Name Language="en-US">Custom XML</Name>

[Code] ...

When I run the report and export it to XML , I got the XML as given below.

       <?xml version="1.0" encoding="UTF-8"?>
       <Report Name="POExportToGermany">
          <SPOrecset>
                 <SPOK_Collection>

[code] ...

Here the format is not in the expected format.

 2. Using Stored Procedure:- Using Stored procedure I am able to  create the expected XML format. 

When i click on this link I can see the data in expected XML format. But the problem is I am not able to show this data in report. Dataset is showing the above .XML as given below. How can I generate report using  SSRS  with expected XML format?  What are the procedures to get the above XML format.