backbone modelbinder converter ajax request

Does anyone know how to cause modelbinder's converter to wait until a ajax request is complete? I'm trying to use backbone's modelbinder on my view but the converter is failing because it is not waiting for the ajax call to complete before rendering

var convertIdToName = function(direction, value) {
   if(direction == 'ModelToView') { 
      $.ajax({url: 'rest/lookup?' + value}).done(data) { 
        return data[0].Name; }
   }
}

var binding = {Id: { selector: '[name=Id]', converter: convertIdToName }};

I fixed this by seting

  async: false 

on ajax request