ok, the role is not 'Datastore.Remove' but 'Datastore.Delete' 
Sorry for the noise, in the vsphere client you see 'Remove datastore' when editing a role, so I assumed it was 'Datastore.Remove' .
ok, the role is not 'Datastore.Remove' but 'Datastore.Delete'
Sorry for the noise, in the vsphere client you see 'Remove datastore' when editing a role, so I assumed it was 'Datastore.Remove' .