(FYI I cross-posted this in OES:Linux - Storage as well but this seems like a better forum. I will update both on resolution.)

I have 2 nodes in a working cluster. They are both using a SBD volume on a shared iSCSI LUN using RDMs. (My servers are all virtual under VMware.)
My problem is that I cannot join a new server to this cluster because I cannot map to the shared disks - they don't show up in the 'connect' list of the VM config. Is there something I'm missing, does NCS mark these LUNs as unavailable for further connects or something? I know that NCS supports up to 32 nodes in a cluster so this is confusing.
I'm thinking of disconnecting the SBD partition LUN from the existing servers, then seeing if I can connect to it from all three....any comments?
Am I limited to 1 node per ESX host per cluster because of RDMs? I have tried SCSI bus sharing without success.