First things first, get the software and install it.
Soft ware available here :
Installation guide available here:
PowerChute Network Shutdown : Installation v.2.2.1 (www.apcc.com)
What isn't mentioned in the install notes, is that the esx firewall will not let your register the device with the UPS.
Open port 80
/usr/sbin/esxcfg-firewall -o 80,tcp,out,http
Now proceed with the install and then close the port.
/usr/sbin/esxcfg-firewall -c 80,tcp,out,http
Ok, after this you should see the new client device listed in the UPS's management web pages.
Now if you leave this as is, you will carry on your busy life feeling you have a slightly less risk of something awful happening should there be a significant power failure.
The port used by the UPS to communicate the shut down event, is closed, your lovely ESX server will never know.
Open the port.
/usr/sbin/esxcfg-firewall -o 3052,tcp,in,PowerChute
Strictly speaking this not no APC's fault, but they could at least put a note, "Check port 3052 is not blocked!".
There is no way to really simulate a Shutdown event for only one device, the agents are devout believers and will not ignore the command to shutdown.
The UPS signals each listed device and also broadcasts it too.
You could shutdown the agent on all other devices and send a Shutdown signal from the management pages. Don't for get to enable the agents after though.
Use nmap to test the port is open :
nmap host -p3052
Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2007-03-12 12:19 EST
Interesting ports on xxx.xxx.com (nnn.nnn.nnn.nnn):
PORT STATE SERVICE
3052/tcp open PowerChute
MAC Address: hh:hh:hh:hh:hh:hh (VMWare)
That's it, Good luck.