in

beforeSubmit

of ue script.. what is correct way to add a line to an existing order (standard mode)? The following yields

Please choose an item to add

user_error.

var R =context.newRecord;  
R.insertLine({ 
   sublistId : 'item',
  line : 1
}); 
R.setSublistValue({
   sublistId : 'item',
   fieldId : 'itemid',
   line : 1,
   value : 3317
});