[Problem] Form helper in Codeigniter v3.0rc

Thanks but I've already read the documentation about the csrf protection. My code is like that (I use Twig template) :

PHP Code:

         $this->data = array_merge($this->data, [
                'page_title'    =>  'Rejoindre la communauté',
                'set_login'     =>  set_value('u_login'),
                'set_email'     =>  set_value('u_email'),
                'set_password'  =>  set_value('u_password'),
                'set_pass_conf' =>  set_value('pass_conf'),
                'csrf_name'     =>  $this->security->get_csrf_token_name(),
                'csrf_hash'     =>  $this->security->get_csrf_hash(),
            ]);

            $this->twig->display('site/user_register.twig', $this->data); 


And my users_panel.twig contains between form tags :

Code:

<div class=" col-sm-offset-2 col-sm-10">
                           <input type="hidden" name="{{ csrf_name }}" value="{{ csrf_hash }}" />
                           <button type="submit" name="submit_new" class="btn btn-primary">S'inscrire<i class="icon-after fa fa-chevron-right" style="color:#FFF"></i></button>
                       </div>

So I don't understant why the access is already refused :/