如何使用不是第二个对象的主键的键创建导航属性

在EF5中，使用代码优先的方法和流畅的API，如何基于不是另一个表的主键的键创建导航属性(多到1)?

我的数据库模型是这样的，和我不能改变它:

• TableFoo1
  • Foo1ID int (key)
  • Field1 int
  • varchar值
• TableFoo2
  • Foo2ID int (key)
  • Field1 int
  • varchar值
• TableBar
  • BarID int (key)
  • Field1 int
  • varchar值

我想要我的这些实体:

public class Foo1
{
    public int Foo1ID { get; set; }
    public int BarID { get; set; }    //It corresponds Bar.ID
    public string Value { get; set; }
    public Bar Bar { get; set; }
}
public class Foo2
{
    public int Foo2ID { get; set; }
    public int BarID { get; set; }    //It corresponds to Bar.Field1, NOT Bar.ID
    public string Value { get; set; }
    public Bar Bar { get; set; }
}
public class Bar
{
    public int ID { get; set; }
    public int Field1 { get; set; }
    public string Value { get; set; }
}

这是我的地图(第二张是不完整的):

public  class Foo1Map : EntityTypeConfiguration<Foo1>
{
    public Foo1Map()
    {
        this.HasKey(e => e.Foo1ID);
        // Links to Bar's Primary Key, yay, it's easy.
        this.HasRequired(e => e.Bar).WithMany().HasForeignKey(e => e.BarID);
    }
}
public  class Foo2Map : EntityTypeConfiguration<Foo2>
{
    public Foo2Map()
    {
        this.HasKey(e => e.Foo2ID);
        // No clues of how to links to Bar's other unique column, but not primary key.
        this.HasRequired(e => e.Bar).WithMany()........?
    }
}
public class BarMap : EntityTypeConfiguration<Bar>
{
    public BarMap()
    {
        this.HasKey(e => e.BarID);
    }
}