Hi Mario,
Thanks for your prompt response.
So, for this case the best way would probably be:
-Enable EVC compatibility on vCenter 5.1 Cluster
-Disable DRS on 5.1 Cluster
-Disconnect old hosts from vCenter 4.1
-Connect new hosts to vCenter 5.1 into existing cluster
-Migrate VM's from old host to new host
-Storage vMotion VM from existing storage to new storage.
- Enable DRS on 5.1 Cluster
Thanks,
David