In a mixing bowl, combine the beef, minced pork, pork skin, pork fat, garlic, shallots, sugar, 1 teaspoon black pepper, and fish sauce. Knead for 5 minutes until all ingredients are well combined. Cover, then refrigerate 1 hour for the flavours to develop. Heat a barbecue grill or char grill pan. With wet hands, divide the mixture into 12 even portions and roll each portion into a sausage shape. Thread the beef sausages onto each lemongrass stick and brush with a little oil. Place on the hot grill and cook the beef skewers for 6 minutes, turning every few minutes, until cooked. Remove the meat from the lemongrass skewers, and distribute 2 skewers per baguette. Spread 1/2 teaspoon each chile sauce and hoisin sauce into each baguette.