I came here because I have the same problem as described by Aaron McVanner above.
After installing RU Host on a Windows Server 2012R2 the host service starts correctly, is set to auto-start and also accepts connections from a Viewer, but it is not showing in the system tray.
And just like he does, I also have VMs and other services running on the machine that prevent me from simply rebooting the system just to get the tray icon working.
It would be great (for other users) if this issue could get fixed so the tray icon shows up even without rebooting. (I have not tried to log off + log on, because there are server apps running under my windows user session)