This XML Security extension implements XML Security (Signature and Encryption) functions using the Apache XML Security library.
There was an issue with this component. Having the jar org.apache.xml.security.utils.XMLUtils.java in the class path changes the way xmlsec generates or serializes signatures. The following page implies you need a patched xmlsec jar for cardspace to import the cards.
We are pursuing a CQ to get the new version of xlmsec approved. (IPR approval is based on the specific version.)
To see the full email thread with more details on this issue please look here.