SubSonic 3 SimpleRepository One-to-many

How do I handle relations in SubSonic 3 using SimpleRepository? E.g: Having Author and Book (see below) I want the assigned Author to be persisted when the Book is persisted.

[Serializable]
public class Book
{
    public int Id { get; set; }
    public string Title { get; set; }
    public Author Author { get; set; }
}

[Serializable]
public class Author
{
    public int Id { get; set; }
    public string Name { get; set; }
}

Apparently this is not possible, according to this post.