IModel instance = engine.getTemplateInstance();
Resource instanceResource = instance.getModelResource();
EObject javaRoot = instanceResource.getContents().get(0);
EObject javaClass = javaRoot.eContents().get(0);
EStructuralFeature memberFeature = javaClass.eClass().getEStructuralFeature("members");
List<EObject> classMembers = (List<EObject>)javaClass.eGet(memberFeature);
assert(Util.getElementName(classMembers.get(2)).matches("p2"));
EObject fieldP2 = classMembers.get(2);
EObject fieldP4 = EObjectCopier.copyElement(fieldP2, fieldP2.eClass().getEPackage());
fieldP4.eSet(fieldP4.eClass().getEStructuralFeature("name"),"p4");