EClass docEClass = ExtendedMetaData.INSTANCE.getDocumentRoot(testPackage);
EObject doc = EcoreUtil.create(docEClass);
resource.getContents().add(doc);
EStructuralFeature docMixedFeature = ExtendedMetaData.INSTANCE.getMixedFeature(docEClass);
FeatureMap docMixed = (FeatureMap) doc.eGet(docMixedFeature);
AnyType test = (AnyType) EcoreUtil.create(XMLTypePackage.Literals.ANY_TYPE);
docMixed.add(ExtendedMetaData.INSTANCE.demandFeature("urn:test", "test", true), test);
SimpleAnyType subTest1 = (SimpleAnyType) EcoreUtil.create(XMLTypePackage.Literals.SIMPLE_ANY_TYPE);
test.getMixed().add(ExtendedMetaData.INSTANCE.demandFeature("urn:test", "subTest", true), subTest1);
subTest1.setInstanceType(XMLTypePackage.Literals.STRING);