Sure. Add an "iframe" option to your form options and it will force the iframe-mode of submitting the form (which uses multipar/form-data).
var options = {
iframe: true,
// other options...
};
$('#myForm').ajaxForm(options);
Mike
This is generating a server side error. It seems that if I do not upload a file, the JQuery Form method, posts the form normally encoded instead as multipart/form-data. Can this be avoided?

