How do I add some underlined accelerators to menu items?

  menubar1 = gtk_menu_bar_new ();
  gtk_object_set_data (GTK_OBJECT (window1), "menubar1", menubar1);
  gtk_widget_show (menubar1);
  gtk_box_pack_start (GTK_BOX (vbox1), menubar1, FALSE, FALSE, 0);

  file1 = gtk_menu_item_new_with_label ("");
  tmp_key = gtk_label_parse_uline (GTK_LABEL (GTK_BIN (file1)->child),
                                   _("_File"));
  gtk_widget_add_accelerator (file1, "activate_item", accel_group,
                              tmp_key, GDK_MOD1_MASK, 0);
  gtk_object_set_data (GTK_OBJECT (window1), "file1", file1);
  gtk_widget_show (file1);
  gtk_container_add (GTK_CONTAINER (menubar1), file1);

  file1_menu = gtk_menu_new ();
  file1_menu_accels = gtk_menu_ensure_uline_accel_group (GTK_MENU (file1_menu));
  gtk_object_set_data (GTK_OBJECT (window1), "file1_menu", file1_menu);
  gtk_menu_item_set_submenu (GTK_MENU_ITEM (file1), file1_menu);

  new1 = gtk_menu_item_new_with_label ("");
  tmp_key = gtk_label_parse_uline (GTK_LABEL (GTK_BIN (new1)->child),
                                   _("_New"));
  gtk_widget_add_accelerator (new1, "activate_item", file1_menu_accels,
                              tmp_key, 0, 0);
  gtk_object_set_data (GTK_OBJECT (window1), "new1", new1);
  gtk_widget_show (new1);
  gtk_container_add (GTK_CONTAINER (file1_menu), new1);