DefaultPacketExtension content (XEP-0027)

Hello,

I'm having a hard time trying to implementXEP-0027 with Smack. While trying to discover XEP-0027 support I try to get this extension from Presence:

<presencefrom='pgmillard@jabber.org/wj_dev2'to='jer@jabber.org'>
  <status>Online</status>
  <xxmlns='jabber:x:signed'>
    iQA/AwUBOjU5dnol3d88qZ77EQI2JACfRngLJ045brNnaCX78ykKNUZaTIoAoPHI
    2uJxPMGR73EBIvEpcv0LRSy+
    =45f8
  </x>
</presence>

I do get the extension by calling:

PacketExtension xs = presence.getExtension("x", "jabber:x:signed");

if (xs != null && xs instanceof DefaultPacketExtension) {

                                        DefaultPacketExtension dxs = (DefaultPacketExtension)xs;

}

If the extension is found I want to verify the signature. But how do I access the content of the extension? There seems to be no support for doing so?

Please help!

Thanks!

Henning