// .. don't bother cloning, just attach it
DiagramLayoutPart target = new DiagramLayoutPart(new PartName("/diagrams/layout1.xml"));
target.setJaxbElement(
XmlUtils.deepCopy(source.getJaxbElement()) );
gloxPackage.addTargetPart(target);
// DiagramLayoutHeaderPart
DiagramLayoutHeaderPart diagramLayoutHeaderPart = new DiagramLayoutHeaderPart();
ObjectFactory factory = new ObjectFactory();
CTDiagramDefinitionHeader header = factory.createCTDiagramDefinitionHeader();