I registered Template Virt VMware Guest and Template Virt VMware to some ESXi host, connecting directly to ESXi hosts (I don't use our VCenter).

Some items are reported 'Enable' :

• vmware.vm.cluster.name[{$URL}, {HOST.HOST}]
  * vmware.eventlog[{$URL}]
  * vmware.fullname[{$URL}]
  * vmware.vm.hv.name[{$URL},{HOST.HOST}

  ]

• vmware.version[{$URL}]

But all others are reported as 'Not Supported', ie :

• vmware.vm.memory.size.ballooned[{$URL}, {HOST.HOST}]
  * vmware.vm.storage.committed[{$URL},{HOST.HOST}

  ]

• vmware.vm.memory.size.usage.guest[{$URL}, {HOST.HOST}

  ]

It's same behaviour for ESXi 4.1.0 and 5.1.0