Thanks, I found the red choices.
Your description is correct; the one in JRemote is not. It sais "Tap the blue arrow for more server options, including commands for shutting down ...", but there is no blue arrow. You have to tap the i-circle or gray arrow next to it.
So far, so good, except that the shutdown doesn't seem to work in my system. It is now 10 min since shutdown, and the PC is still on.
Here is what happens: After the shutdown command, there appears a box on the PC display "Do you really want to shut down?" with a Yes/No option to click. Since the PC is headless (no display), this is not seen and the PC just sits there waiting. I traced this with Microsoft Remote Desktop.