* Method createXMLPlanNested.
* @return MappingNode root of mapping doc
*/
private static MappingNode createXMLPlanNested() {
MappingDocument doc = new MappingDocument(true);
MappingElement root = new MappingElement("Catalogs"); //$NON-NLS-1$
doc.addChildElement(root);
MappingSequenceNode sequence = new MappingSequenceNode();
MappingElement cats = sequence.addChildElement(new MappingElement("Catalog")); //$NON-NLS-1$
MappingElement items = cats.addChildElement(new MappingElement("Items")); //$NON-NLS-1$
MappingSequenceNode sequence0 = items.addSequenceNode(new MappingSequenceNode());