It will work fine (and is supported) with FC, I've done this on different vSphere versions.
However, I never tried it with FCoE. Even if this would work, keep in mind that it is NOT supported (not even in vSphere 5.1), so I would not recommend to use it in a production environment.
The following environments and functions are not supported for MSCS setups with this release of vSphere:
- Clustering on iSCSI, FCoE, and NFS disks.
- ...
André