Do a second library load

PHP Code:

$this->load->library('uploadlib',array('dir'=>'uploads/biblioteca/','tipos'=>'pdf|doc|docx|txt'));
       
$livro='livro';
$value=$this->upload($livro);
if(!$value)
    return false;
$this->data['error'] = null;
$this->data['upload_data_livro']=$value;
       
$this->load->library('uploadlib',array('dir'=>'images/capas/','tipos'=>'gif|png|jpg')); 


Second time

PHP Code:

$this->load->library('uploadlib',array('dir'=>'images/capas/','tipos'=>'gif|png|jpg')); 


doesn't load the parameters because uploadlib already loaded! how can i fix this? I) want to load the upload lib with the news parameters.
Thanks in advance