If the pronto can connect; then you should be able to send a text stream to the ftp. It sounds like you only need to format 'ftp commands' properly in a text string and send them to the ftp server to get this to work.

If the OZ weather service is like most other countries: Do they give out the weather via RSS feeds? If you're only looking for the highlights, RSS is pretty easy to parse over http and it might be quicker than diving into the ftp solution.