The difference between Add and Update in SubSonic3 SimpleRepository

I've had reports of this - can you add this (and your code) as an issue please?

I think you missed one of the core ideas of DI here. That idea being the use of interfaces to abstract the calling code from the concrete class that actually implements the functionality.

public interface IDataRepository { }

internal class DataRepository : SimpleRepository, IDataRepository
{
}

ObjectFactory.Initialize(
    x => x.ForRequestedType<IDataRepository>()  
        .TheDefaultIsConcreteType<DataRepository>()  
        .CacheBy(InstanceScope.Hybrid));

Now all the client code should resolve/reference only the IDataRepository interface.