将属性添加到Zend表单文件元素

I am working with Zend Form, and i would like to add some attributes to a file element, this is my Zend element :

$cv = new Zend_Form_Element_File('cv');
 $cv->setDestination($config->path->cv);
 $cv->addValidator('Count', false, 1);
 $cv->addValidator('Size', false, 10240000);
 $cv->addValidator('Extension', false, 'doc,docx,jpg,pdf');
$cv->setDecorators(array('ViewHelper'));
$this->addElement($cv);

I have tried with $cv->setAttrib('name','value'); but it doesn't work too

Do you have any idea ? Thanks

I have had un bug in my Zend Library, thats why i couldn't add attribute to input file. Thanks