orm - Many to Many relation in Entity Framework doesn't retrieve the related collections -

i'm trying map many many sql relation in entity framework using code first.

here classes:

[table("b3_360viewerdata")]

public class viewerdata : entity  {      //.... other properties ...//       // navigation property      public entitycollection<feature> features { get; set; } 

}

[table("b3_feature")]

public class feature : entity {

   //.... other properties ...//    // navigation property    public icollection<viewerdata> viewerdata { get; set; } 

}

create table [dbo].[viewerdatafeatures](

[feature_id] [int] null,

[viewerdata_id] [int] null

)

the insertion in table went expected, when want retrieve viewerdata entity don't features collection populated null.

am missing something?