S list2 = createCategory();
list2.setDate(toXmlDate(end));
getElements(list2).add(e2);
EventListType events = new EventListType();
accessor.getCategories(events).add(list1);
accessor.getCategories(events).add(list2);
File f = accessor.getDataStore().getDataFile(start);
accessor.getDataStore().write(events, f);