Combine first 5 ingredients in a large saucepan; bring mixture to a boil. Reduce heat; simmer, uncovered , 10 minutes . Set sauce aside.
Prepare charcoal fire in smoker, and let burn 10 to 15 minutes . Place water pan in smoker; fill with 1/4 cup sauce and 1 quart water
Trim skin from roast. Place roast on food rack, and baste generously on all sides with sauce. Insert meat thermometer, being careful not to touch bone or fat.
Cover with smoker lid; cook 9 to 11 hours or until meat thermometer registers 170°, basting frequently with sauce after 6 hours. Refill water pan with additional sauce as needed. To serve, thinly slice roast.
Note: Remaining sauce may be refrigerated and reheated for basting other meats.