VocabularyElementType elementType = new VocabularyElementType();
AttributeType at = new AttributeType();
at.setId("someid");
DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document document = builder.parse(new ByteArrayInputStream("<mynode>value</mynode>".getBytes("utf-8")));
document.normalizeDocument();
at.getAny().add(document.getDocumentElement());
document = builder.newDocument();
Element el = document.createElement("myelement");
el.setTextContent("howdy");