Eager loading problem with domainservice

Question

I have 3 tables:

Tab1(ID1, ID2, Message1 ...):  ID2 is foreign key from Tab2
Tab2(ID2, ID3,Message2...):  ID3 is foreign key from Tab3
Tab3(ID3, Message3, ...)

Then I use domianservice to generate metadata and query.

In Entity Tab3 metadata, attribut [Include] is added on the navigation property Tab2.

In Entity Tab2 metadata, attribut [Include] is added on the navigation property Tab1.

In query method, code like:

var result =  this.ObjectContext.Tab3.Include("Tab2").Include("Tab1").
              Where(e => e.EngagerID == id);
return result;

in xaml binding is set as:

Binding="{Binding Tab3.Tab2.Tab1.Message1}"

I can't get the data.

If binding is like

Binding="{Binding Tab3.Tab2.Message2}"

or Binding="{Binding Tab3.Message3}"

I can get the data.

I have done this with previous version of domainservice and it's fine. any limitation for this kind of the path deepth? How to resolve this problem?