The translated versions are unofficial, I did not make them. I hope to make official translated versions soon. However I think you could try to replace the Portuguese language files with the Spanish language files.
There is most likely a "tl" folder containing translation files. I would imagine there would be a Portuguese and Spanish version. Simply copy the Spanish files into the Portuguese folder and replace.
I hope that works, but I am not sure if they translated it in normal translation files or if they hardcoded the translation. You might need to ask on the site you got the translated version from for help since they made it