Here's what I do - split a couple vanilla beans lengthwise, scrape out the contents and add with the bean pods to a fine mesh nylon bag. Add the bag to the fermenter after fermentation is done. Taste every day until the flavor is slightly more than you want (because vanilla flavor fades over time), then pull the bag and package. I also sometimes add the bag to a keg instead - same process. I wouldn't boil personally - you'll lose a lot of the delicate character.