This is the only infor I could find: "Pale, wheat and caramel malts are blended with natural vanilla flavor to provide a rich and creamy body. The result is a refreshing ale with flavors reminiscent of an old-fashioned Creme Soda."
it might be worth contacting the brewer for some tips. Baring that you could just make a pale ale (light on the hops) and add some vanilla extract or vanilla beans to taste.
Check out The Mad Fermentationist
for my adventures in fermentation (cheese, bread, ginger beer plant, and of course plenty of funky beer).