My knowledge is pretty weak in the SSL area, so I don't really have much advice. I don't test GSP under SSL. I am not aware of any problems, but I can't remember hearing anyone say they are using SSL, either. But I would have guessed I would have heard about it if it didn't work.
About the only thing I can think of is to try some basic troubleshooting. Can you navigate to one of the static files using SSL? Are there any other sites using SSL, and do they work? Check your application properties in IIS Manager to make sure everything looks right.
If you figure it out, please let us know what it was. I would like to know one way or the other whether GSP works under SSL. If not, I should try to figure out what the issue is.
Roger Martin
Creator and Lead Developer of Gallery Server Pro