Heat the oil in a large heavy pan. Add the ginger and vegetables, and saute for 5 minutes. Meanwhile, soak the wakame for 4-6 minutes, then chop roughly. Add the water or stock, and chopped wakame, to the vegetables the pan. Cover and bring to a boil, then reduce heat the heat and simmer for 15 minutes, or until the vegetables are just tender. Cream the miso with about 8 tablespoons of the broth; stir into the broth and remove the pan from the heat. Serve immediately, garnished with chopped parsley. Do not reheat miso soup.