Preheat the oven to 135 degrees C top / bottom heat.
Place the meat in a large roasting pan and spread the onions on top.
Mix Worcestershire sauce, liquid smoke or smoked salt, garlic powder, salt and pepper in a bowl, then add cola. Then pour into the roaster. Pour water on the meat and put the lid on the roasting pan.
Roast the meat in the oven for 4 to 5 hours. After 4 1/2 hours, check whether the meat can be pulled well with a fork.
When the meat is done, pull it apart with two forks, place in a bowl and mix with the barbecue sauce.
Put the meat in baguette rolls, place on a plate and serve with the coleslaw.