Yes it's part of the grain bill. Just click on Add Grain/Extract and pick your grain & amount.
There is one particular bug though. Special B is marked in the database as a "must mash" grain, when in fact it is a type of caramel/crystal malt.
So for any other extract recipe that DOESN'T include Special B, you can select "Extract" as the recipe type and it will be fine. For any extract recipe that includes Special B you will get a little exclamation point in the list telling you it's the wrong recipe type.