Thank you. :-) Yes, I've read this manual. But if I understand it correctly, it states the same restriction I am experiencing:
on page 17, it says:
2 Click the New device drop-down menu, select RDM Disk, and click Add.
3 Select an unformatted LUN.
4 Select a datastore.
This datastore must be on a SAN because you need a single shared RDM file for each shared LUN on
the SAN.
5 Select Physical as the compatibility mode.
and on page 18:
2 Click the New device drop-down menu, select Existing Hard Disk, and click Add.
3 In Disk File Path, browse to the location of the quorum disk specified for the first node.
4 Select Physical as the compatibility mode and click Next.
To me, it reads like this is the same way as I had to do it: using the same RDM files on all nodes, not "copies" of the RDM files.
An other info, if of interest at this point: my cluster is not an Windows cluster, it's an OES11 cluster. I'm not sure whether it matters here, because the sharing issue seems to be a VMWARE issue (RDM file locked), not an issue of the cluster's OS.