The directory structure and po files have been created, however as far as I know no-one is working on the translation for pt-BR. Po2xml is a command line tool, only available on *nix systems as far as I know. You shouldn't need po2xml to work on the translation, it's just used to build the docs. Translated files can be contributed as a patch file in JIRA (you may need to create a new JIRA issue for this).
I use ubuntu and I found that command into the package 'poxml'