You can turn off SC discovery in vmware plugin...VIBE_DISCOVERY_something is the option. If you set this to N then the config file will never be updated and it should work with -actual. Only problem is then we arent detecting if you move a VM to a new datastore so you would have to update config manually and add new datastores / storage systems when they are added.
If you want to set all the volumes into "manual" state, set:
This will prevent the update of VOLUMES, SNAPMIRROR_VOLUMES, SNAPVAULT_VOLUMES and NTAP_DFM_DATA_SET. If you want to set those values manually at that point, you can. This will help you if you still intend to use RDMs as the vSphere/vCloud plug-in doesn't support RDMs directly. The risk element is that if you move the VM from one Datastore (backed by a volume) to another and that isn't in your VOLUMES parameter, it will be quiesced/unquiesced but not be backed up from a NetApp snapshot standpoint.