Vanilla Beans

I plan on making my regular porter next week, but I want to add a couple of vanilla beans.  My question is when should I add the beans?  I thought that I read somewhere on here that they should be added to fermenter, but I can’t remember if you should wait until most of the fementation has been completed.  One more, should I split the beans open as well?

What I did for my one and only vanilla porter was to split 3 vanilla beans, cut them into inch long pieces and soak them in 1/2 cup of Maker’s Mark bourbon for as long as the beer was in primary, probably about 3 weeks.  When  I kegged the beer I poured the bourbon into the keg. 
I’m not a fan of vanilla flavored beers but my daughter gave me the beans for Christmas last year and asked me to brew something with them.  So I did and was amazed at how good the beer was.  My vanilla porter is on my schedule to brew again pretty soon.
That was a 10 gallon batch-the other 5 gallons got about a pint of coffee.  I roasted the beans, ground 1/3 pound of them, and steeped them in 170F water.  I added the coffee directly to the other keg.  I have to say that those 2 kegs have been some of my most popular ever among my friends and family.

From Denny’s Bourbon Vanilla Imperial Porter (here: http://wiki.homebrewersassociation.org/BourbonVanillaImperialPorter)…

“When primary fermentation is complete, split 2 nice fresh vanilla beans lengthwise.  Scrape out and reserve all the seeds and “gunk” in them.  Cut the pods into roughly 2-3” pieces and add the pods, seeds and “gunk” to a secondary fermenter.  Leave them there until you get the amount of vanilla flavor you like.  I usually start tasting at about a week and a half, and may leave them in until 2 weeks.  You may want to let them go a bit more than you think is necessary since the vanilla flavor fades with time."

My wife just made a stout with vanilla & coffee.  I believe she used 2 vanilla beans that she slit lengthwise then added to the secondary fermentor for a week or two.  The flavor was definitely different than using vanilla extract.  It worked out very well.

Thanks- I think I’ll just add them to the secondary as mentioned.