What does not work? Any error message?
I've the same problem --> No error message, everything looks good but nothing happens. It just does not set the GID nor UID.
To be a bit more clear:
1.) Create a new directory NewDir
2.) Goto Properties of NewDir
3.) Set 2775 (in any combination: With/Without "Add X to directories", With/Without "Set group, owner and permissions recursively") and apply
4.) Check permissions: Everything will be set but the GID :-(
I hope that is enough information to reconstruct the problem.