You can map the RBD using standard commands
rbd map .. and then create a SR on it using
type=lvm shared=true and using device from
Since the kernel is 4.19, most of ceph rbd features are supported. And, by using LVM backend, you would retain XCP functionality.
However, you will loose native snapshots or other rbd based image manipulation features due to absence of focussed RBDSR plugin.
Edit: I don't know if such SR can be created from XO but you can surely create it using CLI
xe sr-create command.