// Server-provided tests
  public static MappingScriptProxy getTestEmptyMappingModel() {
    try {
      URL url = new URL("http://www.europeana.eu/schemas/edm/EDM.xsd");
      XMLSchema source = getXSDSchema(url);
      url = new URL("http://www.openarchives.org/OAI/2.0/oai_dc.xsd");
      XMLSchema target = getXSDSchema(url);

      MappingScript mapping = getEmptyMapping(source, target, null);
      Mapping2UIAdapter adapter = new Mapping2UIAdapter();
      return adapter.adapt(mapping);
    } catch (IOException e) {
      return null;
    }
  }
  public static MappingScriptProxy getEmptyUserMappingModel(String source, String dest) {
    try { // usar getSchema??
      URL url = new URL(source);
      XMLSchema sxml = getXSDSchema(url);
      url = new URL(dest);
      XMLSchema dxml = getXSDSchema(url);

      MappingScript mapping = getEmptyMapping(sxml, dxml, null);
      Mapping2UIAdapter adapter = new Mapping2UIAdapter();
      return adapter.adapt(mapping);
    } catch (IOException e) {
      e.printStackTrace();
      return null;
    }
  }