Hi,
I just started my first Unraid build with a Proliant Microserver too.
I am using with the beta 4.7 (just saw that a stable release was available now).
I have only the stock 1 Gb of RAM so preparing the disks tooks some time. 2 x WD20EARS and I left the stock 160 Gb that came with it to practice replacing disks.
The power button works for powering up (obviously) but also for shutting down nicely.
Seems to be working nice so I will upgrade soon to a Plus registration key.
Cheers,
Laurent