public function GetCustomImportModel() {
      $Header = $this->GetImportHeader();
      $Source = GetValue('Source', $Header, '');
      $Result = NULL;

      if (substr_compare('vbulletin', $Source, 0, 9, TRUE) == 0)
         $Result = new vBulletinImportModel();
      elseif (substr_compare('vanilla 1', $Source, 0, 9, TRUE) == 0)
         $Result = new Vanilla1ImportModel();

      if ($Result !== NULL)
         $Result->ImportModel = $this;

      return $Result;
   }