Do you mean in the Playing Now tree?
This will show all DLNA servers and renderers on your network so if your Plex installation is either a DLNA server or a renderr it will show up in JRiver as either an external libray to play from or an external renderer to play to.
Thanks, yes it looks as though it is showing as an external library.
Now I have just tried gizmo on my iPad with some success as in I can control playback from the iPad. I can tell it to play out of the computer audio out or play on the iPad. Now if could make it play, via gizmo/ipad to my oppo 103 I will have come a long way. The oppo 103 appears on both devices, the Mac with jriver and the iPad w/gizmo. I can push to the oppo from the Mac/jriver or pull from the Mac/jriver via the oppo onscreen UI.
The oppo shows up on iPad under gizmo as a player/play to option and I can select the oppo and select a song but it will not play. Any ideas? I get a little closer everyday!