OK, I have a problem which I wish to solve, but I alone seem unable to.... I can create ExternalIds without issue, and I can check in my code if the ExternalId Class even exists, but I want to be able to create and destroy these classes depending on what else is loaded elsewhere in a plugin or my other plugins.   List the classes Type[] types = Assembly.GetExecutingAssembly().GetTypes(); List<Type> myTypes = new List<Type>();