Try to run the Format utility directly. It will give you a list of partitions which can be formatted. If it isn't in this list either, the GVP probably does not support big HDDs, neither through NSD nor through NSDPatch (SCSI-Direct or TD64) or the necessary entry is missing from Devs:NSDPatch.cfg. You should install the Boingbags in order to get all the latest drivers and NSDPatch entries.
Bye,
Thomas