civm createmetadata fails with " Tag is not expected in requests for version VERSION_5_1."

Hi all,

I'm following the directions in this (excellent) article: http://blogs.vmware.com/vipowershell/2012/03/working-with-vcloud-metadata-in-powercli.html

which is the only documented way I've found to add metadata to vms or vapps with PowerCLI.

The article refers to a future version of Powercli (5.5).

When adding the metadata with createmetadata method, PowerCLI (5.1) returns the following error:

Exception calling "CreateMetadata" with "1" argument(s): "<Value> Tag is not expected in requests for version VERSION_5_1."

Does anybody know the correct way to add metadata in PowerCLI 5.1 (which is the current release)?

Best Regards

Emiliano