You may want to take the fleece out, for now--it's soft and comfy and very tempting for an untrained bunny to use as a litterbox. They often like to lay where the go to the bathroom.
How big is Benny and is he neutered? Also, how old is he? If he's a bigger rabbit, a larger litterbox may be better for him rather than a corner one. And if he's young, the training my take some time and patience. If he's a bit older and not neutered, then hormones could make him not care about using the litterbox.
Either way, for now I'd make sure his timothy hay is next to the litterbox so he has to eat it while sitting there. You can also put some hay right on top of the litter so he can poo and munch at the same time (which rabbits like to do). Keep picking up any stray droppings and putting them in the box and soak up any pee with a tissue and put it in the box as well. Eventually he should get the idea.