[jQuery] Problem with jQuery: AJAX interface / ajaxForm plugin file upload combo.

[jQuery] Problem with jQuery: AJAX interface / ajaxForm plugin file upload combo.


Dear Jquery devs,
I got a slight but complex problem. and I think I need someone
experienced with ajaxForm for it. I use the nifty AJAX interface
( http://www.visionmasterdesigns.com/tutorial-ajax-interface-menu-using-jqueryphp/
), and i'd like to make my CMS (webshop) in this interface.
For this I use Jquery and PHP.
Everything so far has worked out quite good. Only 1 slight problem :
the $_FILES['fileimage'] variable doesn't seem te get posted.
Normal $_POST variables such as $_POST['txtname'] do get posted.
Working code with a link for stuff inside the content:
$('.content a').click(function() {
                 var content_show = $(this).attr("title");
                 var id = $(this).attr("id");
                $.ajax({
                 type: "get",url: "includes/admin/mediator.php",data:
"page="+content_show + "&sleep=0" + "&id=" + id,
                 success: function(html){
                 $(".content").html(html);
             }
        });
});
Now with the form:
var options = {
     beforeSubmit: showRequest
     };
    $('#addcategoryform').ajaxForm(options);
    function showRequest(formData, jqForm, options) {
     var queryString = $.param(formData);
     alert(queryString);
     $.ajax({
                type: "post",
                url: "includes/admin/mediator.php",
                data: queryString + "&page=procescategory&sleep=1",
                success: function(html){
                $(".content").html(html);
     }
    });
     return false;
    }
For me the problem is obvious, if you look at the "data:" argument,
the file doesn't get put into the arguments.
The normal arguments do get posted through and I can use them in the
procescategory page.
Does anyone know how to post a file manually or a work-around? I
already tried ajaxSubmit, but doesn't seem to work either.