Cooking oil would do as its not going to wreck your seals.
If your fussy get extra virgin olive oil, if not vegatable cooking oil would do.
I'm surproise that is says not to use grease as there are MANY types and as above oil will venetually disappear and leave your seals dry.
What service intervals do they suggest?
How about some Teflon bike lube? Finish Line do a "Dry Teflon Lube" which goes on wet (obviously!) but then dries to leave an teflon impregnated oil film. Been using that for years on the mountain bikes during the drier months as it works really well, also used it on my HKS SSQV to keep it lubed.

Don't know if you were being serious or not, but I really don't like the idea of using WD40 for any kind of lubrication outside of things like door-hinges. It's technically for displacing water (WD = Water Displacer). In comparative terms, it's not actually a very good lubricant. It is however very good at releasing seized bolts etc. If ever I was lubricating anything of high performance (like bike chains etc) I would always use a specialised lubricantIs is just wd40 lol
Infact, looking at the instructions I'd say this is a specialist type lube.
If its quite wattery then its most likely:-
Mineral Seal Oil or Pale Spindle type base with a small amount of corrosion inhibitor, friction modifier and extreme pressure additive. It may even have a tacky additive to stop it from running off the components.
I'd get the proper stuff if I was you.

i think you could be rite not easy to get hold of this tho![]()