I have this set up and working. However I thought that volume backups would be intercepted by the pluggin if resident on managed storage. This does not seems to work for me, with all volume backups still being processed by the cloudstack export ova process. Is my understanding correct?
The VSC can do backups at the VM level (i.e., not the volume level) for VMs hosted in a VMware environment. In essence, what you are seeing is the correct behavior. Would VM-level backups satisfy your use case, or are you strictly looking for volume-level backups?
I have not tested a VM backup with multiple volumes attached. If this backs up the VM and the volumes then that is ok as I can stipulate volumes need to be mounted to be included in the backup. I do currently have a lot of customers who have unconnected volumes.