Anything that you can do with VMware Power CLI, you can do with WFA. WFA Vmware commands essential use VMware Power CLI itself to connect to a vCenter Server and execute commands.
User guide for the cmdlets are available here: http://www.vmware.com/support/developer/windowstoolkit/wintk40u1/html/
Currently there are no certified commands from WFA to create the VMDK disks but you can easily create one. I can post a command to do it if you want.
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