One thing to remember with ESXi 5.5, all of the new features are ONLY available using the web client. Also, once you update the hardware version of your virtual machines, you will only be able to edit settings in the web client. I was told by a VMWare rep that in version 6, due probably about this time next year, will only be accessible by the web client. The vSphere client is going away.
Cheers
Rob
The answer is always "PEBKAC!