Put 1/2 cup of water in a large saucepan and bring to a simmer over medium-high heat. Add the shrimp and gently cook through. Add the peas and soybeans to warm. Lower the heat and swirl in the butter. Add the reserved pasta, lemon juice and chives and gently toss together. Add salt and white pepper to taste. Serve garnished with oregano and piave vecchio.