Help with nlapiMergeRecord

Hi All,

I am trying to use the nlapiMergeRecord and nlapiSendEmail API's to merge and send a customer's details

I have no problem in sending the email template to the customer but none of the fields are mergin onto the email template???

below is my code

 function executeSavedSearch(){    //locate the saved search   var searchresults = nlapiSearchRecord('customer', 3178, null, null);        for (var i = 0; searchresults != null && i < searchresults.length; i++) {    //locate some values of the saved search     var customerid = searchresults[i].getId();    var companyname = searchresults[i].getText('companyname')         nlapiLogExecution('DEBUG', 'Getcompany', 'company id is: ' +  customerid + ' and the company name is: ' + companyname);         merge_fields_arr = new Array();              //I have got'NLADDRESS' referenced on my template but is not replicating on the adress on send of email   merge_fields_arr['NLADDRESS'] = 'TEST ADDRESS';               var emailbody = nlapiMergeRecord( 92, 'customer', customerid, null, null, merge_fields_arr).getValue();      nlapiSendEmail(138006,