* When encoding an XACML 2.0 PolicySet, the namespace
uri isn't written to the stream.
PolicySet set = ...
ByteArrayOutputStream out = new ByteArrayOutputStream();
The PolicySet is correctly written into 2.0 format, but
when reading the xml stream the data is interpreted as
a 1.0 (=default) PolicySet.
To determine the xacml version; getNamespaceURI() is
evaluated --> AbstractPolicy (ln 263)
* There are other remarks in the code (eg constructor
AbstractPolicy) referring to the fact that metaData
handling isn't finished yet.
// FIXME: this needs to fill in the meta-data correctly
metaData = null;
(AbstractPolicy ln 180)