Drain crabmeat, reserving liquid. In a small bowl, combine crabmeat, cheese, and Italian seasoning. Brush a wonton wrapper with the beaten egg. Place about 1/2 teaspoon crab mixture in the center, and fold wrapper diagonally to create a triangle. Press edges to seal. Transfer to a flour-dusted baking sheet. Repeat until all of crab filling has been used; this should make about 32 ravioli.
Bring a large pot of salted water to boil. Meanwhile, in a large saucepan, combine milk and reserved drained crab liquid over medium-high heat. Whisk in sauce, add butter, and bring to a boil. Reduce heat and simmer, stirring frequently, for 3 minutes. Keep sauce warm over low heat while you boil the ravioli. In batches of 8, drop ravioli into boiling water. Cook for 2 minutes, or until ravioli rise to the surface. With a slotted spoon, carefully transfer ravioli to sauce. Repeat until all ravioli are cooked. Divide ravioli equally among 8 plates. Sprinkle with parsley and serve.