Good luck; as you inferred previously, as it's not shown on the parts list, it may well be part of the clutch hub itself, although that would be surprising if it can be detached from the hub.
Looking again at the parts diagram, not only is the outer race not shown separately from the hub, but the hub and primary gear were sold only as a matched pair, on a single part number.
Does the outer race look like it's designed to be removed (e.g. circlip, etc.)?
If not, potentially it could have been cast into the hub, in which case it's not going anywhere.
Is it in really poor shape?