Combine first 7 ingredients in a small mixing bowl, and mix until well blended.
Remove the fell (tissue-like covering) from roast with a sharp knife. Place roast in a 15- x 10- x 1-inch jellyroll pan; pour marinade over roast. Marinate 2 hours, turning roast every 30 minutes.
Line a shallow roasting pan with aluminum foil; lightly grease rack of roasting pan. Place roast, fat side up, on rack. Insert meat thermometer, if desired, being careful not to touch bone or fat.
Combine jelly and pineapple in a small saucepan. Cook over low heat until jelly dissolves. Baste roast frequently with jelly mixture. Bake at 350° until desired degree of doneness: about 1 1/2 hours or 140° (rare); about 2 1/2 hours or 160° (medium); about 3 hours or 170° (well done).
Transfer roast to a serving platter. Cool slightly. Garnish as desired.