can you help me with the Vietnamese charset. I use this but it doesn't work well. // Custom characters replacement for Vietnamese char-set $this->url_replace = array( 'Á' => 'A', 'á' => 'a', 'À' => 'A', 'à' => 'a', 'Ả' => 'A', 'ả' => 'a', 'Ã' => 'A', 'ã' => 'a', 'Ạ' => 'A', 'ạ' => 'a', 'Â' => 'A', '...