jquery + setting accept header question

I've got a rails app and am using facebox to submit ajax forms. If I submit the form in an inline manner (eg. not facebox) the form works properly and the div gets updated.

However, if I submit the form in a facebox, the accept headers are html and not javascript, and the response is handled in a html manner (eg. the user is redirected to another page).

My question is what am I missing where the accept header on the facebox forms is not being set to text/javascript?

Here's my js: #application.js $j(document).ready(function(){

      var options = {            target: 'form#message_form'           // beforeSubmit doesn't work for either a facebox form request or inline form.           // beforeSubmit: function(xhr) {xhr.setRequestHeader ("Accept", "text/javascript")}         }

       $j('form#message_form').livequery(             function() { $j(this).ajaxForm(options)}         ); }

// add Accept:text/javascript header to jQuery ajax requests $j.ajaxSetup({ 'beforeSend': function(xhr) {xhr.setRequestHeader ("Accept", "text/javascript")} })