We get the Roast beef or ham with our own bread.
Swiss Cheese or amazingly the Cheese Sauce is soy free.
We got the apples but found out that the yogurt dipping sauce that comes with the apples contains soy.
And of course the not healthy, but soy free kraft macaroni and cheese.
http://www.arbys.com/food/ingredient-allergens.pdf (dated july 2013)