Resource.Factory.Registry reg = Resource.Factory.Registry.INSTANCE;
			Map<String, Object> m = reg.getExtensionToFactoryMap();
			m.put("xxx", new XMIResourceFactoryImpl());

			// Obtain a new resource set
			ResourceSet resSet = new ResourceSetImpl();

			// Create a resource
			Resource resource = resSet.createResource(URI
					.createURI(cdu.getNome()+".xxx"));
			// Get the first model element and cast it to the right type, in my
			// example everything is hierarchical included in this first node
			resource.getContents().add(cdu);

			ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
			
			// Now save the content.
			try {
				resource.save(baos, Collections.EMPTY_MAP);
				//resource.save(Collections.EMPTY_MAP);
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}

			IFolder folder = targetFolder;
			IFile file = folder.getFile(cdu.getNome()+".xxx");
			InputStream source = new ByteArrayInputStream(baos.toByteArray());
			file.create(source, IResource.NONE, null);