You'll find in the manual that Rohloff tells you to service the EXT box (black box on hub, removed with thumbwheel) every 500km. This is ten times as often as you change the oil. As I've said elsewhere on this forum, even for a German that is an excessive amount of CYA.
Perhaps Herr Rohloff never met Phil Wood.
I too fill the entire cavity of the EXT box with Phil's to the extent that a tiny amount squeezes out when I remate the surfaces, as Dan does, but I wipe it out and refill it every time I change the gearbox oil (once a year or every 5000km/3000m), which is a convenient interval for me. I've never seen the slightest sign that the Phil needed to be changed more often, or even that it wouldn't go another year, or two or three. The cavity is large enough so that the grease at the working surface (the big brass nut on the gearbox axle and the matching socket in the removable EXT box) thins out to act as a moving parts machine grease and at the margins acts as waterproofing. I've never found any water in there.
I agree with Paul and also the Australian advice Dan found: Those parts are so substantial compared to the forces going in, grease or not is probably irrelevant. I grease because I live in clean, almost dust-free countryside, where water is a far bigger threat.
As always, I advise those with Rohloffs under guarantee to do as the manual tells them, and after the guarantee runs out to vary this particular service from the manual's injunction only if you're comfortable with the thought that it may cause Rohloff to send you a bill if your hub ever breaks.