XML signature and KeySelectors class: howto ?

[shadens]

Hi Community,

I sign a XML message (really, soap message) and then I sent it
to the server. The server could validate XML signed, but verification
fails (server say that signature is invalid :( )
The strange is if I implement signing line code and validate line in
same class, then all works (and signature is valid);
I think the problem it is in follow few lines:

DOMValidateContext valContext = new DOMValidateContext(new
KeyValueKeySelector(), signatureTag);
^^^^^^^^^^^^^^^^^^
 XMLSignature signature =
sigFactory.unmarshalXMLSignature(valContext);
 // Validate the XMLSignature (generated above)
 boolean isSignatureValid= signature.validate(valContext);

The KeyValueKeySelector is a private static class (within main
classes) that extends KeySelectors. It seems on client side method of
this class are executed automatically and validate the signature; if I
move validation on server side, this class seems not is automatically
executed
O_o
What is the magic of KeySelectors class??

Thanks to all!

P.s.
Ide: netbeans 5.5
AS: Sun Application Server 9.0
package: XML Signature Api