/**
  * Generates a PHP call to an object helper.
  *
  * @param string The helper name
  * @param string The column name
  * @param array  An array of parameters
  * @param array  An array of local parameters
  *
  * @return string PHP code
  */
 function getPHPObjectHelper($helperName, $column, $params, $localParams = array())
 {
     if (null !== ($map = $this->getParameterValue('maps.' . $column->getName()))) {
         // Load map
         $params['map'] = $map;
         $helperName = 'select_map_tag';
     }
     return parent::getPHPObjectHelper($helperName, $column, $params, $localParams);
 }