reclaim storage from VMFS volume

Hi

We have a NetApp FAS8020 array where we present Fibre channel LUNS to ESX.

For the NetApp suite we have the option to reclaim space using the NetApp Virtual Storage Console vcentre plugin however this is only supported on NFS volumes.

Is there any other way to reclaim space on Fibre based LUNs using VMFS?

I have tried the ESXi CLI tool vmfkstools -y command however whilst this runs, it doesn't ever reclaim the space.

We are using ESXi 5.0.0 U3 both Hypervisor and vCentre level.

Many thanks