BeerSmith adds all fermentables added up to primary as part of the OG & ABV calculations. Anything added as secondary or at bottling is not calculated.
In BeerSmith 3, you should have the fruit in the fermentables database and the "type" should be fruit or juice, depending on what your using. If they're not already installed, you can find whole fruits, juices an and wine bases in add-ons.