Thanks for posting!
To clarify did you enable SSL in the FileMaker Server admin console? That option refers to SSL for FileMaker Pro clients. To enable SSL for web clients, you'll need to set it up on the web server side (IIS or Apache depending on the operating system).
If I could clarify, it's supported to just install the SSL certificate in IIS as normal? Is there any other configuration that I need to do? Also, does this apply to the login page as well?