1. Stir together lite soy sauce and jerk seasoning. Place roast in a 2-gal. zip-top plastic freezer bag. Pour soy sauce mixture over roast. Seal bag, and chill 2 to 12 hours, turning occasionally.
2. Preheat grill to 350° to 400° (medium-high). Remove roast from marinade, discarding marinade. Pat roast dry with paper towels. Let stand at room temperature 30 minutes.
3. Stir together brown sugar blend sweetener and bourbon in a microwave-safe glass measuring cup. Microwave at HIGH 1 minute or until sugar blend is dissolved, stirring after 30 seconds.
4. Grill roast, covered with grill lid, over 350° to 400° (medium-high) heat 25 minutes. Baste with brown sugar blend mixture; turn and baste other side. Grill, covered with grill lid, 20 minutes or until a meat thermometer inserted into thickest portion registers 145°, basting after 10 minutes. Remove from heat, and let stand 10 minutes before slicing.
Note: For testing purposes only, we used Splenda Brown Sugar Blend Sweetener.