Jquery Overlay and php form

Jquery Overlay and php form

I have a form that is loaded into an overlay using thsi code
$("a[rel]").overlay({
onBeforeLoad: function() {
                  // grab wrapper element inside content
var wrap = this.getOverlay().find(".contentWrap");

// load the page specified in the trigger
wrap.load(this.getTrigger().attr("href"));
}

});
The form is straight PHP with PHP error checking and a thank you for submit message. I want the the error messages and the thank you for submitting message to stay in the overlay. How do I do that?
<form method="post" action="<?php echo $_SERVER['PHP_SELF'];  ?>"