Finder shows a Folder (Directory) but Server/Websites does not

I have a directory /opt, which shows in Finder, however when I use 10.8.1 Server.app and attempt to point a web site to that directory, it is not visible.

"Obviously," Server.app has a hard coded list of directories it will show. I know Finder itself has such a list, and it is easily verified via terminal.

The basic question is -- how does one change that to display the other directories.

I assume there is a "write defaults" command to enable this.