I configured my OpenE as Master.
With WinNUT Client 1.5 installed on my XP i can monitor my UPS connected to Open but it doesn't give me a lot of information (only STATUS)...
I'll try to make my own "shutdown" module managed by WinNUT and let OpenE shutdown himself.
If yours engineers integrate "Network Shutdown Module" in OpenE it's really a very good point for your software because this module is compatible with VMware ESX, Virtual Center, Windows, Linux etc...