Problem of retrieving signature element using XPath expression ha ving different namespaces

[Hess Yvan]

Hi,

I have a problem to retrieve the Signature element of my signed XML document
using XPath expression. My document looks like that:

<?xml version="1.0" encoding="UTF-8"?>
<edoc:e-document xmlns:dcmi="http://www.imtf.com/e-document/dcmi";
xmlns:edoc="http://www.imtf.com/e-document";
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; version="1.0">
<ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#";>
  ....
</ds:Signature>
   <edoc:metadata>
      <dcmi:DCMI>
 
<dcmi:identifier>urn:hypersuite:EFECD0FF-C0A8021C08DEE071-D030940E</dcmi:ide
ntifier>
         <dcmi:date>1966-07-20</dcmi:date>
      </dcmi:DCMI>
      <edoc:custom>
         <edoc:customer>333777</edoc:customer>
         <edoc:account>333777.0</edoc:account>
         <edoc:account-manager>Giraffe aile</edoc:account-manager>
         <edoc:amount>123456789.10</edoc:amount>
         <edoc:type>Savane</edoc:type>
      </edoc:custom>
   </edoc:metadata>
</edoc:e-document>

I would like to retrieve my signature element using the XPath expression
"/edoc:e-document/ds:Signature", but it fails because the namespace "edoc"
is not known if I use 

Element nscontext = XMLUtils.createDSctx(xmlDocument, "ds",
Constants.SignatureSpecNS);
sigElement = (Element) XPathAPI.selectSingleNode(xmlDocument,
signatureLocation, nscontext);

and it fails also if I use 

sigElement = (Element) XPathAPI.selectSingleNode(xmlDocument,
signatureLocation);

How can I solve the problem (I don't want to use "//ds:Signature") . It seem
to be a problem of Xalan XPath API....

Thanks for your answer

Yvan