Roll the pork shanks in the seasoned flour and fry gently in the olive oil until light and golden brown. Add onions and garlic and sauté until the onions are soft and transparent. Add the remaining ingredients, except potatoes, carrots and beans. Cover with a lid and simmer for 1½ - 2 hours over low heat until tender. Add boiling water or a little more chicken stock if the sauce cooks away. Add the vegetables 30 minutes before the end of the cooking period, and simmer until the pork shanks and the vegetables are soft. Serve with crusty bread rolls, couscous, rice or pasta.