Disable HTML Select Option in Zend Form

We can do that using the setAttribs function in the Zend Form Element

   Ex:
      $roles = new Zend_Form_Element_Select("roles");
      $roles->setLabel("Roles");
      $roles->addMultiOptions(array('1' => 'Admin', '2'=>'Group Admin','3'=>'User'));
      suppose if we want to set it disable if the user is 'User'.
          if($roleValue > 2)
        $roles->setAttribs(array('disabled'=>'disabled'));

How to pass variable with _redirector helper zend framework

$this->_helper->_redirector('action','controller','module',array('param1'=>'value1'));