For 7.1 you should run "aexnsagent.exe /resetguid" after cloning to force agent to request a new ID from the server. Theoretically if your cloning mechanism creates a clone with a different MAC address then you should be fine. This information is used to create a unique machine idenitification info - the resource keys.
In 7.5 the new ID will be requested automatically if resource keys change.
I think VMWare creates clones with different MAC addresses, so /resetguid should be enough.