Property Transfer Attribute in Soap Response

I am trying to transfer an attribue value from a soap response using XPath.
The response is

   <soap:Body>
      <ListResponse xmlns="http://sword-insurance.com/openplus/documentservice">
         <ListResult>&lt;Root>&lt;Documents>&lt;Document DocumentKey="166946" EntityKey="419" EntityInstanceKey="300818" EntityViewKey="5300" FileName="ITSD166946.doc" DocumentType="1" DocumentName="Contact" UserName="Richard Martin" Note="" ExportBitField="" />&lt;/Documents>&lt;/Root></ListResult>
      </ListResponse>
   </soap:Body>

and my transfer is

declare namespace ns1='http://sword-insurance.com/openplus/documentservice';
//ns1:Document@DocumentKey

When I execute the transfer I get an Xpath sytax errror at char 15 on line 2
Can anyone suggest what I have wrong here?

Richard