public function addUser($login, $password, core_kernel_classes_Resource $role = null, core_kernel_classes_Class $class = null){

        $this->checkCurrentUserAccess($role);
    	if (empty($class)){
    		$class = $this->getRootClass();
    	}
    	
        $user = $this->generisUserService->addUser($login, $password, $role, $class);
        
        //set up default properties
        if(!is_null($user)){
            $user->setPropertyValue(new core_kernel_classes_Property(TaoOntology::PROPERTY_USER_FIRST_TIME), GenerisRdf::GENERIS_TRUE);
        }
    	
        return $user;
    }