You can do it but there will be a little work involved. You'll have to figure out the nutrient breakdown of each ingredient in your sauces dressings and total it all up. Then go to "Create a Custom Food" and add the info. I always include how much I consider a serving to be in the title of my custom food. For instance, you could call it "Andouille Saus BBQ 1/2 cup" just so you'll know exactly how much it is because when it is added to your list of food, it isn't as clear as with the other foods.
It's a little bit of work, but once you figure it out it will always be in there for next time.
"It may be normal darling, but I'd rather be natural." -Holly Golightly