I haven't seen any fully synthetic oils solely sold for diesel. Just some which are for petrol and diesel.
That's what you want to use - dual rated oils. You do NOT want to be using a diesel-only oil, since most of those, particularly in your part of the world, will have no gasoline approval and will be completely different from a normal CJ-4 type diesel lube. You don't want to be using a diesel only CF-2, CF type lube in a gasser or "normal" diesel. This
is the type of lube you definitely want to avoid. I haven't seen such an oil in synthetic only, either. Maybe Doug or Charlie have, but I certainly haven't.
If you want a sensible synthetic HDEO, I'd stick with a proper dual rated one from Shell, Chevron, Castrol, or Mobil.