a simple convention
public class NoForeignKeys : IReferenceConvention, IHasManyConvention
{
public void Apply(IManyToOneInstance instance)
{
instance.ForeignKey("none");
}
public void Apply(IOneToManyCollectionInstance instance)
{
instance.Key.ForeignKey("none");
}
}
// use it
AutoMap.AssemblyOf().Conventions
.FromAssembly() or .Add(typeof(NoForeignKeys))