Projection into Known Type

I created a test query against NorthwindIB. If I run the query without using a known type, then it returns the expected data. But when I add the EmployeeSlice, then it returns the correct number of entities, but there is no data in the entities. I am currently using version 6.1.5. The EmployeeSlice is defined on the Server project, and linked to the SL project.



var query = em.Employees.Select(emp => new EmployeeSlice()
            {
               EmployeeID = emp.EmployeeID,
               FirstName = emp.FirstName,
               LastName = emp.LastName
            }
               ).ExecuteAsync((results) =>
               {
                    foreach (var employee in results.Results)
                    {
                        //Return returns 9 slices, but all data is empty.
                    }
               });

[DataContract]
    public class EmployeeSlice : IKnownType
    {
        public int EmployeeID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }

Great, thanks.