Tranlation Files in system and aplication folder

[eluser]Alfredo Palhares[/eluser]
Hello. I made my own Portuguese Translations of the Code Igniter (by the way the portuguese translations in myGengo aren't well made, i send a message to the responsible and suggested mine)
So, I put them in system/language

But i made some plug-ins and i need custom form validate messages for it, but i don't want it my "global" folder.

It is possible to have a form_validation_lang.php file in system/application/language and only have my custom errors
like :

Code:

$lang['validate_date'] = 'O campo %s apresenta um formato inválido, por favor introduza um formato válido (aaaa\mm\dd)';

If is possible, is a good practice?

Thanks,
Alfredo Palhares