[NTG-context] Portuguese characters under Mac OS X

Hello folks! I am having a problem processing my ConText files under Mac OS X. I am using TeXShop, and when I render the text written in Portuguese, it does not render the characters with accents. I did not have this problem under Windows, and so I would like to know from any Mac user that typesetts in languages other than english how I can solve this problem. Thanks in advance, Fidel.