You mentioned that with the web services SDK it is not possible to call any methods from the MOR. But what about with Vim.dll that comes with the power shell CLI SDK?
What is the difference between the two? Both namespaces for instance have a "VirtualMachine" type. And from what digging I've done there are many more recommendations to using the Vim.dll - why is that? Isn't the Web Services SDK the newest and most comprehensive of the lot?