Im currently brewing up a raspberry wheat beer, and have read that the best procedure for adding the raspberry is to allow for a primary of 2-3 weeks, then rack/cold crash it for 2 weeks...Then rack it onto your raspberry pulp and let it ferment on that for 2 weeks at normal temps - I think the goal of this technique is probably to stunt the yeast, and hopefully allow more raspberry flavour to come through - This is all speculation though, as I am about to rack onto the raspberries in the next few days, and dont really know how it will turn out