You need a 64-bit filesystem and a 64-bit device driver.
The easiest way to achieve this would be to purchase OS3.5 or 3.9. Otherwise, you can probably do it on the cheap by searching Aminet for TD64 and SFS (and I think you need NSDPatch as well). The old v43 public beta 64-bit scsi.device and FFS are no longer available AFAIK.
Chris