In the same skillet over medium heat melt the butter. Mix in the bell pepper, onion, and garlic and saute for 5 minutes. Stir in the flour and sugar and cook for 1 minute. Stir in the wine, vinegar, and water. Mix in the soy sauce, ketchup, and black pepper. Reduce heat to low and let simmer for 5 minutes, or until the sauce has thickened. Return the pork pieces to the skillet and stir until well combined.
