Hello,
so that is not its fault since power management is disabled on your host.
This is greyed out because either hardware does not support power managment or power management by OS is disabled in BIOS (http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1018206)
Sorry I've no further ideas on what could resolve your issue, hope someone else could give you some useful hints.
Regards,
Paolo