c# - Interesting EF4 Code First Many-To-Many Relationship Question -

i have 2 models, report:

public class report {     public int id { get; set; }     public string name { get; set; }      public virtual chargetype chargetypes { get; set; } }  public class reportconfiguration : entityconfiguration<report> {     public reportconfiguration()     {         mapsingletype(r => new { r.id, r.name }).totable("report");          hasmany(r => r.chargetypes)           .withmany(c => c.reports)           .map("report_chargetype", (r,c) => new { reportid = r.id,                                                    chargetypeid = c.id });     } } 

and chargetype:

public class chargetype {     public int id { get; set; }     public string name { get; set; }     public int sortorder { get; set; }      public virtual report reports { get; set; } }  public class chargetypeconfiguration : entityconfiguration<chargetype> {     public reportconfiguration()     {         mapsingletype(c => new { c.id, c.name }).totable("chargetype");          // map sortorder property join table "report_chargetype"         mapsingletype(c => c.sortorder).totable("report_chargetype"); // doesn't work      } } 

i want able map sortorder property of chargetype join table of report , chargetype. have tried many things no success, , know there has way @ loss. else has insight on how done.