Case Messages Search (nlapiSearchRecord) getValue returns null

Please help I am trying to loop though Case Messages using the Search Join between the Case and Messages. There is no error return by my code, but the Message columns have null value when using getValue(). I am firing the code as a test on the pageInit event on Cases.

Here is my code so far:

 var caseId = nlapiGetFieldValue('casenumber');      var filters = new Array;   filters[0] = new nlobjSearchFilter('casenumber', null, 'is', caseId);      var columns = new Array;   columns[0] = new nlobjSearchColumn('recipient', 'messages');   //columns[1] = new nlobjSearchColumn('message', 'messages', null);      var searchresults = nlapiSearchRecord('supportcase', null, filters, columns);      for (var i = 0; searchresults != null && i < searchresults.length; i++)    {    var searchresult = searchresults[i];        var msgValue = searchresult.getValue('recipient');        alert(msgValue);   }