Thanks ... 
But the main problem is I don't want to convert my vCenter VM into vCloud .. Because that will be more time consuming and not good for my flow ..
Basically what I want is to use some of the workflow of vCloud (like "Attach a hard disk") for vCenter VM and for that purpose I was asking the above mention questions ... 
Is there any other way to achieve the same ??? Or if any other method to create the same workflow for vCenter vm ???
Please help me with that ...