URI Language Identifier

[eluser]abada[/eluser]
iam using URI Language Identifier
http://codeigniter.com/wiki/URI_Language_Identifier

but i can`t make languages dynamically

how i can make this

$config['lang_uri_abbr'] = array("es" => "spanish", "en" => "english", "ja" => "japanese");
to

$config['lang_uri_abbr'] = $this>mylib->alllangs();//return array("es" => "spanish", "en" => "english", "ja" => "japanese");

plz help me ??