Currently there are no mortgages available for overseas buyers. The developer sometimes lets the buyer pay over ten years however the interest on the principal is variable and can reach as high as 24% a year
Keep in mind that the 25 year mortgage packet was first introduced in Brazil on the 15th of October 2007, less than two years ago and the 30 year mortgage is even newer so the mortgage market really is in its infancy.
Natural evolution of the mortgage market is expected to lead to mortgages for overseas buyers however how soon that will be implemented is a risky thing to guess at and anyone's opinion is equally (more or less) valid. The truth is people simply don't know.