Success: Under the visible VIs option I added the "*" character as suggested, and now have access. I previously only had the top-level VI added, using it's full directory path name. I assumed that you just needed to add the top-level VI.
I also note that when connecting to the server from the client machine (using the remote server and not the web-enabled browser), you just need to add the name of the top-level VI, and not the full path to it. This is something that I think was also causing problems.
Thanks for the quick response on this!