Adding Subtabs with SuiteScript (Netsuite Help file doesnt work)

Hello Users,
This script is a beforeLoad user event script that is deployed to the Sales Order (it is a sample taken from the Netsuite Help). It all works wel, a new tab appears and in edit mode I can fill in an emailaddress and details. But after pressing save nothing is saved, what am I missing?

 //Define the user event beforeLoad function  function tabsToSalesOrder(type, form)  {  //Define the values of the beforeLoad <em>type</em> argument  if (type == 'edit' || type == 'view')    {      //Add a new tab to the form      var sampleTab = form.addTab('custpage_sample_tab', 'Sample Tab');        //Add a field to the new tab      var newFieldEmail = form.addField('custpage_field_email', 'email', 'Alt Email', null,    'custpage_sample_tab');         //Add a second field to the new tab      var newFieldText = form.addField('custpage_field_text', 'textarea', 'Details', null,    'custpage_sample_tab');        //Add a subtab to the first tab      var sampleSubTab = form.addSubTab('custpage_sample_subtab', 'Sample Subtab',    'custpage_sample_tab');        //Add a select field to the subtab      var newSubField = form.addField('custpage_sample_field', 'select', 'My