How to force the rsync to use my proxy settings?

How to force the rsync to use my proxy settings?

I am installing macports on my Mac OS X and for fetching the binaries from the repository it uses rsync protocol. Unfortunately seems the repository is not accessible by direct connection from my machine. So I ran a local proxy program (supports http, https, ftp and socks) and now trying to find out how to redirect the rsync connection through my proxy. Is there anybody who knows about this? Cheers,