I've been playing with my newly acquired N503 and have managed to write a couple of python scripts to wake it up and shut it down from Xbox Media Center (XBMC).
The WOL is standard send a magic packet stuff.
To do SOL I had to mimic a couple of website calls so it looked as if I was logging onto the web interface as the admin user and then use the showndown option. works like a charm.
In your case its not exactly what you want for remote users having access to the admin account details locally. But if you have a web server up or some other way to connect to your home network, perhaps you could do the same thing?