I can't translate my module

[Isb]

Hi guys, i can't understand why my module is not listed into the translation table.

 

The code below is the same code of the other post:

<?php

if ( ! defined( '_PS_VERSION_' ) ) exit;

class Skema extends Module{

	public function __construct(){
		$this->name = 'skema';
		$this->tab = 'front_office_features';
		$this->version = '1.0';
		$this->author = 'Ivano Mercuri';
		$this->need_instance = 0;
		$this->ps_versions_compliancy = array( 'min' => '1.5.4.1' , 'max' => '1.6');
	 
		parent::__construct();
	 
		$this->displayName = $this->l( 'Modulo Skema' );
		$this->description = $this->l( 'Apporta modifiche al Front End' );
		$this->confirmUninstall = $this->l( 'Lo vuoi disinstallare?' );
	}
	
	public function install(){
		if( Shop::isFeatureActive() ){
			Shop::setContext( Shop::CONTEXT_ALL );
		}
		if ( parent::install() && $this->registerHook( 'displayFooter' ) && $this->registerHook( 'top' )){
			return true;
		}else{
			return false;
		}
	}
	
	public function uninstall(){
		return parent::uninstall();
	}
	
	public function hookDisplayFooter( $params ){
		$link = '<a class="reg" target="_blank" href="http://www.enuage.it/corner/">';
		$testo_popup = sprintf( $this->l( 'Questo sito è dedicato esclusivamente ai rivenditori. Per essere abilitato e consultare i prezzi, registrati %s qui %s.' ) , $link , '</a>' );
		if( ! $this->context->customer->isLogged() && $this->context->controller->php_self == 'index' ){
			$this->context->smarty->assign(	'testo_popup' ,$testo_popup );
			return $this->display( __FILE__ , 'skema.tpl' );
		}
	}
	
	public function hookTop( $params ){
		if( ! $this->context->customer->isLogged() && $this->context->controller->php_self == 'index' ){
			$this->context->controller->addCSS( $this->_path . 'css/skema.css' , 'all' );
			$this->context->controller->addJS( $this->_path . 'js/skema.js' , 'all' );
		}
	}
}

Selecting "Installed modules translations" in BO, both "Core" or theme do not recognize my module strings to be translated.

 

I tried ( by reading this ) to create the folder "/modules/name_of_the_module/translations/iso_code.php"... nothing.
I tried with "/themes/name_of_the_theme/modules/name_of_the_module/translations/iso_code.php"... still nothing.

 

I also tried to uninstall, install, reset, deactivate, activate, delete, upload the module zip, install it once uploaded... for the transtalation table, my module does not exists or it does not have any string to translate

 

Could it be a permission problem?

 

I'll attach my little module if someone want to test it

 

skema.zip