I'm posting the exact entity:

    public class Person : ContactableEntity
{

    public Plan Plan { get; set; }

    public int Record { get; set; }

    public int PersonTypeValue { get; set; }

}

I'm using the following code to update in a disconected context fashion:

        public void Update(DbSet MySet, object Obj)
    {
        MySet.Attach(Obj);
        var Entry = this.Entry(Obj);
        Entry.State = EntityState.Modified;
        this.SaveChanges();
    }

This is a method exposed by my dbContext Called this way:

PersistentManager.Update(PersistentManager.Personas,UpdatedPersona);

The problem is, EF will update any property but the referenced Plan object. Can someone tell me where is the mistake? In advance : the entity reaches the point of update with all the properties correctly set. EF just fails to update the FK in the Database (no exception though)