Working with Dataset

Hi there


               I am getting data from webservice to dataset, In each request i have to take only top 5 records and again i have to merge dataset with new request top 5 records
better understanding refer the code below
but its not working fine whats wrong in this or we can achieve this in any other way please let me know





                sr = new StringReader("WEBSERVICE METHOD").OuterXml);
              
                ds.ReadXml(sr);
          if (Session["TAFResult"] != null)
          & ...