Heat the olive oil and butter. Add shallots and garlic and lightly saute for approximately 1 minute. Add the risotto and stir to coat in the mixture. Add vermouth. Slowly add 2 cups of clam broth at a time, stirring constantly. Do not stop stirring while adding clam broth, scraping bottom to prevent sticking. Toward last 2 cups of clam broth, add all remaining ingredients except seafood and cheese, still stirring constantly. After 40 minutes of constant stirring, when risotto reaches a creamy consistency, add shrimp and scallops. Cook over low heat for 5 minutes, add cheese. Cover and let stand at least 10 to 15 minutes before serving.