In a heavy pan, bring the water to a boil and add the butter beans. When the water returns to a boil, turn the heat down and let the beans simmer for about 45 minutes, or until the skins are tender and the insides creamy, and most of the water has boiled off. While the beans are simmering, make the lemon veloute. In a small pan, heat the chicken stock. Fill the bottom of a double boiler with water, and bring to a boil. Meanwhile, in the top of the double-boiler, set directly over low heat, melt the butter and whisk in the flour. Cook, whisking, for five minutes, then slowly whisk in the hot stock. Place over the boiling water and cook for 45 to 50 minutes, stirring occasionally to keep a crust from forming on top. When the beans are done, add the country ham pieces and cook until the ham is just warmed. Meanwhile, remove the beans from the heat, add the lemon juice, and salt to taste. Remove the beans from the heat, pour the veloute over the beans, and mix well. Serve immediately.