MS remote desktop virtualization: new-RDVirtualDesktopCollection error creating vdi pool

I'm experimenting with my first setup of MS virtual desktop virtualization and have hit a problem I can't get over. I switched over from using the gui to powershell to try and identify the issue. It occurs when I try and create the Desktop collection from the template.

What I have is:

• 1 hyper-v on win 2012 R2 (HyperVServer)
• 1 win 2012 Std server (RDServer) which will have/has each of the other roles involved.
• DCs are our normal DC's in the office here.
• 1 vm with win7sp1pro, patched and updated the integration tools and then sysprepped
• The servers are in spanish

NOTE: I have noticed mention of installing win7 enterprise, which I hope is not a requirement for this to work as I only have pro licenses to experiment with. I can't find this mentioned as being a requirement...

From the RDServer I execute the following:

new-RDVirtualDesktopCollection -CollectionName myVDIPool -PooledManaged 
-Virtual DesktopTemplateName VDIBaseWin7 
-VirtualDesktopTemplateHostServer hypervserver.mydom.com 
-VirtualDesktopAllocation @{"hypervserver.mydom.com"=1} 
-StorageType localstorage 
-ConnectionBroker RDServer.mydom.com 
-VirtualDesktopNamePrefix msVDI

which responds (in spanish - I'll translate below) with

Confirmar
No se concedió acceso a la unidad organizativa CN=Computers,DC=mydom,DC=com. ¿Desea pasarlo por alto y continuar?
[S] Sí  [N] No  [U] Suspender  [?] Ayuda (el valor predeterminado es "S"): s
No se pudieron obtener detalles del escritorio virtual para VDIBaseWin7 del servidor HyperVSrv.mydom.com.
    + CategoryInfo          : InvalidResult: (:) [], WorkflowTerminatedException
    + FullyQualifiedErrorId : JobStateFailed
    + PSComputerName        : localhost

new-RDVirtualDesktopCollection : No se pudo crear la colección de escritorios virtuales. Error:
En línea: 1 Carácter: 1
+ new-RDVirtualDesktopCollection -CollectionName VDIPool -PooledManaged  -Virtu ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException,New-RDVirtualDesktopCollection

It asks to grant access to the computers.mydom.com ou - ok, no problem. But it then fails with "No se pudieron obtener detalles del escritorio virtual para VDIBaseWin7 del servidor HyperVSrv.mydom.com" which translates as:

Unable to obtain details for the virtual desktop for VDIBaseWin7 on server hypervsrv

or

Cannot obtain details for the virtual desktop for VDIBaseWin7 on server hypervsrv

obviously the command is trying to do something remotely with hyperv, but I cannot work out what.

Does anyone have any idea what this command may be attempting to do when it fails? If I had an idea of what it was trying to do I could work out what was wrong, but this doesn't give much info.... 'cannot obtain details' isn't the most helpful of errors.

edit: I've tried trawling through the powershell code in C:\Windows\System32\WindowsPowerShell\v1.0\Modules\RemoteDesktop and other places looking for the source to the function to try and work out what its doing, but no luck, can't find it anywhere.