assigning attributes to a dataset table

Here is a simple webservice returning a dataset with a table (MyTable1) containing one coloumn (ID) as xml.
I would like to assign some attributes to both 'MyTable1' and 'ID'.
How to do that

See below - sourcecode, existing xml response, desired xml response:

Hope you get the point - or ask me to clarify... Thanks;-)

Sourcecode:
---------------------------------------------------------------------------
[WebMethod]
public DataSet MyDataSet()    
{
    DataSet ds = new DataSet("MyDS");
               
    DataTable dt = new DataTable("MyTable1");
    dt.Columns.Add("ID");
    ds.Tables.Add(dt);

    DataRow datarow = ds.Tables["MyTable1"].NewRow();
    datarow["ID"] = "Test";
    ds.Tables["MyTable1"].Rows.Add(datarow);

    return ds;
}
------------------------------------------------------------------

Xml response:
-------------------------------------------------------------------
<?xml version="1.0" encoding="utf-8"?>
<DataSet xmlns="http://tempuri.org/">
  <xs:schema id="MyDS" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
     .........................
     .........................
  </xs:schema>
  <diffgr:diffgram xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" xmlns:diffgr="urn:schemas-microsoft-com:xml-diffgram-v1">
    <MyDS xmlns="">
      <MyTable1 diffgr:id="MyTable11" msdata:rowOrder="0" diffgr:hasChanges="inserted">
        <ID>test</ID>
      </MyTable1>
    </MyDS>
  </diffgr:diffgram>
</DataSet>
--------------------------------------------------------------------------

Desired xml response:
--------------------------------------------------------------------------
<?xml version="1.0" encoding="utf-8"?>
<DataSet xmlns="http://tempuri.org/">
  <xs:schema id="MyDS" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
     .........................
     .........................
  </xs:schema>
  <diffgr:diffgram xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" xmlns:diffgr="urn:schemas-microsoft-com:xml-diffgram-v1">
    <MyDS xmlns="">
      <MyTable1 diffgr:id="MyTable11" msdata:rowOrder="0" diffgr:hasChanges="inserted" customAttribute="content">
        <ID attribute1="Content" attribute2="etc.">test</ID>
      </MyTable1>
    </MyDS>
  </diffgr:diffgram>
</DataSet>