BeerSmith sees fermentables as a pound (or 120 gm) of sugar dissolved per gallon (or liter). This is expressed as percentage yield. Pure sugar dissolves to make 1 gallon of 1.046 solution. This is 100% yield, or efficiency, of sugar extraction per pound of goods added.

Your gravity is slightly more than 1 lb of sugar dissolved to make 1 gallon, but you can still use the figure of 100% yield in the ingredient profile. Your brewhouse efficiency should be raised a little, to account for the slight increase in sugar per gallon.

So, the juice potential is still 1.046 (100% yield) in the ingredient database. When you enter the juice, BeerSmith will calculate as a pound value. Given the ratio above, all you do is enter the pounds as if they're gallons. In other words, 5 pounds = 5 gallons.

The manual part of the equation is to simply subtract the gallons of juice from the total water needed (or fully replace it). Just keep the pound to gallon ratio at 1:1.