Prepare smoker to run at 275 degrees. Cut pork into pieces and season with BBQ rub. Add orange juice, achiote, vinegar, salt, chili powder, oregeno, red pepper flakes, lime juice, garlic and onion to a blender and puree. Form a "basket" with the banana leaves over an aluminun half pan. Pour marinade over pork, and place in smoker for 1 hour. Remove from smoker, fold banana leaves over pork and tie to form a basket. Return to smoker for 4-5 hours or until tender.