Hi Jorge,
The correct answer is to collaborate on the Portuguese language pack here:
http://i18n.osticket.com/
But your contributions will not show up in osTicket / osTicket Awesome until a future release.
Unlike osTicket, osTicket Awesome makes it (fairly) easy to edit the language pack(s) you are using. Simply to to include\i18n\, find your pack and start editing.
I can’t really give you more info than that because it is out of the scope of the types of support I can provide here. But you should be able to figure it out. And yes, you’ll lose your edits if and when you install an upgrade in the future, so be sure to back them up!