Plex Subtitles

Does anyone know how to send a command to Plex to toggle subtitles?

I have been using OpenHab 2 with Habpanel as a replacement for my Harmony One that died a few months ago. I have the Plex plugin generally working with one exception, the ability to toggle subtitles. I looked through the documentation for the Plex plugin but didn’t see anything for turning the subtitles on or off. It is entirely possible that I could be missing something though.

It looks like the Plex API sort of does it. I’m not really sure if that is relevant here, or if it is how to even get it to work through HTTP requests.

The Plex Home Theatre software is running on a Mac mini, the IR port used to handle the remote commands. The set up hasn’t changed aside the switch from IR controlled and Plex plugin controlled configurations.