code: public void saveValue(
          final String contentId,
          final String contentPath,
          final String locale,
          final String value,
          final AsyncCallback<String> asyncCallback) {
  
          CmsRpcAction<String> action = new CmsRpcAction<String>() {
  
              @Override
              public void execute() {
  
                  start(0, false);
                  getService().saveValue(contentId, contentPath, locale, value, this);
  
              }
  
              @Override
              protected void onResponse(String result) {
  
                  stop(false);
                  asyncCallback.onSuccess(result);
  
              }
          };
          action.execute();
      }
docs: Saves a value in an Xml content.<p>
  
  @param contentId the structure id of the content
  @param contentPath the xpath for which to set the value
  @param locale the locale for which to set the value
  @param value the new value
  @param asyncCallback the callback for the result