code: public void createSubEntry(final CmsClientSitemapEntry parent, final CmsUUID structureId) {
  
          CmsSitemapTreeItem item = CmsSitemapTreeItem.getItemById(parent.getId());
          AsyncCallback<CmsClientSitemapEntry> callback = new AsyncCallback<CmsClientSitemapEntry>() {
  
              public void onFailure(Throwable caught) {
  
                  // nothing to do
              }
  
              public void onSuccess(CmsClientSitemapEntry result) {
  
                  makeNewEntry(parent, new I_CmsSimpleCallback<CmsClientSitemapEntry>() {
  
                      public void execute(CmsClientSitemapEntry newEntry) {
  
                          createSubEntry(newEntry, parent.getId(), structureId);
                      }
                  });
  
              }
  
          };
  
          if (item.getLoadState().equals(LoadState.UNLOADED)) {
              getChildren(parent.getId(), true, callback);
          } else {
              callback.onSuccess(parent);
          }
      }
docs: Creates a new sub-entry of an existing sitemap entry.<p>
  
  @param parent the entry to which a new sub-entry should be added
  @param structureId the structure id of the model page (if null, uses default model page)