Improved vMotion in vSphere 5.1 - data moving vMotion

I heard about the new and improved data moving vMotion in the VMworld keynote and wanted to try it out in the home lab. The improvement consists of vSphere being able to perform a simultaneous vMotion+svMotion so you can change both datastore and host at the same time.

I was expecting this feature to be available from the vSphere client by right clicking the VM and choosing 'migrate'. However, this is not the case. The option is there but it is greyed out stating that the VM has to be powered off to perform this action, see screenshot below:

I found an article on yellow-bricks pointing towards the vSphere web client. And for a deep dive, see this post by Frank Denneman.

From the vSphere web client the option is available by right-clicking the VM and choosing 'Migrate', see below.

One apparent limitation is that you cannot migrate between Datacenters, only between cluster within a given Datacenter.

Other than that, the feature works as expected. I did a vMotion plus datastore move from local storage to shared storage. This is the second feature (here's the first one) I've found that is only available in the vSphere web client and not in the vSphere client which leads one to assume that VMware is actually serious about moving future administration away from the vSphere client.