In a small bowl, whisk the mustard, wine, brown sugar, vinegar and soy sauce until well blended. Gradually whisk in oil. Stir in dill and pepper. Place salmon in a shallow glass dish. Pour 2 cups marinade over salmon. Cover and refrigerate for 1 hour. Cover and refrigerate remaining marinade for basting.
Drain and discard marinade. Using long-handled tongs, moisten a paper towel with cooking oil and lightly coat the grill rack. Place salmon skin side down on grill. Grill, covered, over medium-hot heat or broil 4 in. from the heat for 5 minutes. Baste with some of the reserved marinade. Grill or broil 7-9 minutes longer or until fish flakes easily with a fork, basting occasionally.