Preheat grill to medium high heat. In a small bowl combine the Dijon, honey, mayonnaise, salt, and pepper. Place halibut steaks on grill and brush with Dijon Honey sauce. Grill 4 minutes per side, basting frequently. Fish should flake easily with fork when finished. Place rolls on grill, butter side down, for 1-2 minutes, or just until toasted. Remove rolls to a serving platter. Place a halibut steak on the bottom of each sandwich roll, sprinkle with fresh dill and top each with 1/4 cup of the greens. Place top of sandwich roll on each sandwich. Slice each sandwich in half diagonally and serve.