I see the unmanaged() method in the life cycle object now (didn't know this was there before). I also notice it is not being invoked anywhere.
I can make use of this method to help the storage framework determine if it should send a message to the hypervisor in use to create an SR (or datastore for VMware). By the way, if I set the StoragePoolType of my plug-in to Iscsi, exceptions are thrown. I think CloudStack is trying to handle my storage in a way it shouldn't when that value is used.