being an abstract class, I add a Type property, show at Json

serialization (thought it could have been done automaticaly)

SalesCatalog/Model/Product.cs

@@ -32,6 +32,8 @@ namespace SalesCatalog.Model
 		public Period CommandValidityDates { get; set; }
 		public abstract string[] GetSalesConditions();
 
+		public virtual string Type { get { return GetType().Name; }
+		}
 	}
 }