Soak the beans overnight. Drain them and cover with fresh water, then cook until they are tender but still holding their shape, about 1-2 hours depending on the age of the beans. You can add a touch of baking soda to the water.
Heat the oil in a deep, thick bottomed stew pot and fr the sausage until golden brown. Add the garlic and rosemay, then turn down the heat and stir in the onions. Cover with the lid and cook gently for about 15 minutes, giving the occasional stir until the onions are soft and light brown.
Pour in the chicken stock, the drained bean and season with salt & pepper. Bring to a relaxed simmer and cook for around 20 minutes, skimming as necessary. Stir in the two cremes and the kale, mixing well, then simmer for 10 minutes covered. Adjust the seasoning adding the mustard, then simmer for another 10 minutes, uncovered.