<samlp:Extensions xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol">
  <myns:AttributeList xmlns:myns="urn:test:mynamespace">
    <myns:Attribute name="UserName" value=""/>
  </myns:AttributeList>
  <myns:ExampleElement xmlns:myns="urn:test:mynamespace" name="AnotherExtension" />
</samlp:Extensions>