Propper yeast starter is just a LME with some yeast nutrient added. I have a can I picked up at HomeBrewCon this past June, but have not used it yet.
According to the instructions, you dilute the contents of the can to 1 liter and it produces a 1 liter starter. In terms of entering it into BeerSmith, I would just use it as a straight sub for LME.