Is it possible to refine the translation?

Is it possible to refine the translation?

Is there any configuration session that allows some translation edit?

I found a typo in Brazilian Portuguese button label and I was planning to fix by myself...

The button is "Register" at the Customer Portal first access (where you define the password)
Actually I found "Registo" that's wrong
The correct should be "Registrar" or "Registro" (<-- kinda weird)

Thanks!