How to add an external power button?

[foresto]

I used a multimeter to confirm that the innermost corner hole is connected to the on-board power button, and its neighbors to ground. I then soldered in a 2-pin header (2.54mm pitch) and used a matching jumper to attach a pushbutton switch. The NAS case has a hole for an IR receiver, but since I don't use one of those, I used the hole for the switch. M5 threads fit through the hole nicely.

Now I have an easy-to-see, easy-to-press, software-controlled, red power button. Mission accomplished.