Cannot enable service for Power User and User
The bootstrapping of cloud service is explained in: http://support.citrix.com/proddocs/topic/ccpb-20-map/ccpb-bootstrapping.html
Master user can only enable the service for the account. "Enable Service" means showing an intent to signing up for the cloud service. When enabled, all users of the account - who has right roles, will be able to browse the catalog and able to provision resources.
HTH.





