You're doing it wrong. It's not vermouth, it's Kina Lillet, which I'm fairly certain isn't made any more. Any Lillet Blonde will work. Also, it's not with a lemon, it's with a twist- lemon rind. Also, don't shake it. Shaking ruins the body of the Lillet and basically turns it to shit. The only drink Bond had shaken was a vodka martini.