In a saucepan, combine brown sugar and cornstarch. Slowly whisk in vinegar. Add juice and soy sauce. Bring to a boil and reduce heat. Stir constantly until sauce thickens. Add in vegetables and pineapple tidbits. Cook for 10 mins and add to slow cooker.

Bake meatballs at 350 degrees for 50 mins. After they are done, add meatballs to the sauce in the slow cooker.