I would go with only adding them to the secondary, and I would also suggest using a campden tablet in water to sanitze them, or forgoe the sanitization and wash them really well. If you choose to pasturize the berries @ 170º you will have pectin haze issues, so if you want a clear beer you will have to use pectin enzyme to remove the haze.
If you are adding them to the secondary there is a good chance that an infection will not occur due to the alcohol already produced during primary fermentation, and you will have a true secondary fermentation from the sugars in the fruit so the yeasties will normally out-compete any nasties that may be in there, however, there is always a possibility of infection.
No matter what you decide be sure to freeze your fruit and thaw it at least once, this will help to break the cell walls in the fruit allowing the yeast easier access to the natural sugars available.
FWIW, I brewed a blackberry ale a couple of months ago, and it turned out spectacular. I did not bother with sanitizing the fruit, I rinsed the berries very well under cool running water in a collander, I allowed them to completely dry, I than placed them into ziploc freezer bags and placed them into the freezer. I thawed them (I only thawed them once, but I want to try and freeze/thaw twice next time), I then pureed the berries in the Cuisinart before adding them to the secondary on racking day.
This beer turned out to be a hit among friends, I would also plan on allowing the beer to condition about twice as long as usual ~6weeks, fresh fruit adds a little sour flavor until it begins to meld and mellow a bit.
Brew on, Brew strong