[wgong]

If we assume that the NAS is connected to a simple mains power timer to turn it on then off an hour later, then all we need is a simple timer & relay circuit to detect that 5V standby is present, switch the relay on for ~5 seconds and then switch the relay back off. The relay terminals would be connected to the soft power switch terminals. A little PCB with a 555 timer, 5V relay and a few capacitors and resistors should do the trick.

Before the power is shut off by the external timer something else would have to use the administration menu or debug commands to shut the unit off.