You could use your existing VC to host the management cluster VMs and VC for the vCloud.
Then use the new VC purely for the cloud environment. As mentioned previously this will allow your current vc to continue but more importantly you now have a seperate administration route for your cloud environment meaning a greater granularity of roles and responsibility. Also you may well have additional licenses etc for your cloud env that will now be purely on the cloud vc and wont be confussed elsewhere.