I seem to have a similar problem. 8080 works fine, but restricting it to 8443 I get weirdness in Authoring, i.e., Preview doesn't preview but pops up the file download dialog and asks if I want to save grouping.do. I'm using the following environment:
lams2 package installed via apt-get with http://downloads.lamsinternational.com/debian web/ in my sources.list
From the download dialog it appeared that it was trying to use the correct port with the wrong protocol, saying that the file was from http://my.server.edu:8443.
It's been a few months since this post, so I'm hoping you've found a resolution.
Posted by Matt Richardson