I\'m using xmlseclibs to try and sign a SOAP document, but it does not seem to canonicalize things in the same way depending on whether I\'m signing or validating.
I\'ll
You are creating the DOM document improperly and trying to use the invalid in-memory tree. Either serialize and use the serialized result or properly create the namespace declarations in the tree before trying to sign. See the bug report for more information: http://code.google.com/p/xmlseclibs/issues/detail?id=6