@P.Camps and @B.Huynh,
We are still working to reproduce and isolate the issue with SCVMM 2008 R2 created VMs and the "Cluster Migration" Wizard in WS.2012, renamed the "Copy Cluster Roles" Wizard in WS.2012 R2. I will let you know if we are able to repro and isolate the issue.
If it is possible, I recommend that you attempt to test the Cluster Migration Wizard / Copy Cluster Role Wizard scenario with a test VM in your environment.
If you experience an issue with any VM in this scenario, I am keenly interested learning further details! Please email me at: robhind@microsoft.com if you find an issue, and I will follow-up with you offline.
-Rob.