From what the repair article states, you won't be able to any more. You'll really need to watch what you are putting in the tank.
@biodiesel has the luxury of having a gigantic tank that a typical owner isn't going to have or fathom the idea. While great in his case, it's not realistic for the rest of us. Especially with a warranty. I could see them using this against us for fuel system related problems down the road. No receipt, you need to pay $$$$, because that's how it works. They can write it in the repair manual as such. If new HPFP pump goes pop, "customer using wrong type of fuel". Service manager asks customer for receipts of fuel and the customer can't produce it, then warranty voided. Customer needs to pay out of pocket.
As an example... How about for those gas engine lovers... imagine if there was some recall that was done on a truck, and all of a sudden, oh, you need to use 91+ octane fuel only? No more 87. How would folks feel about that? But you bought the truck stating all over the place 87 octane is fine to use, and that is how you intended to use it, now you need to make sure you only use 91+ octane fuel. That's just horse poopy.
It's really a bait and switch tactic. I know it's not going to sit well with some people. Like I said, it doesn't bother me too much in my daily driving (mostly local; not many biodiesel blend stations), but if I do travel, the current manual states I can use up to B20, and I bought the truck to use B20, I should be allowed to use B20 for energy conservation and to save money.