Greetings,
If you haven’t sorted things out by now, WordPress, in general, is very port 80 dependent. In fact, multi-site requires port 80. Our target for compatibility is standard WP deployments, so running http on non-http ports is a buyer beware.
Should this be an unbendable requirement for you, look into hacking plugins_url, home_url, and site_url to support non-standard ports since the RPX plugin relies on those functions heavily.
Cheers!