Here's a recipe, that I've yet to try, taken from a small cookbook that I purchased while visiting the Alma Libre Bookstore in Puerto Moreles titled:
Yucatecan Cuisine of the Hacienda Teya, 2nd edition, 2002. ISBN: 970-605-260-7
Cochinita Pibil (koh-chee'nee-tah peebeel) Pork in Banana Leaf
Serves 8
6.5 lbs pork (leg or loin)
2 pkgs achiote paste
2 cups sour orange juice
Oregano leaves
Salt
Pepper
Garlic
1 lb finely chopped red onion pickled in sour orange
2 banana leaves
1 lb refried beans
1 habanero pepper
Cut the pork in pieces about the size of an egg. Season with salt, pepper and garlic. Dissolve the achiote paste in sour orange juice and add to pork. Let stand hour or more. Place banana leaf in bottom of cooking pot; add meat and oregano leaves and cover with remaining banana leaf. Use aluminum foil to seal and bake at 325 degrees for about 2 hours.
Serve with refried beans and onions, accompanied with tortillas and habanero pepper.