Namespaces in XML OK in Firefox, not IE or Safari?

Namespaces in XML OK in Firefox, not IE or Safari?

I'm using jQuery 1.4.2 and attempting to parse an RSS XML file via AJAX. In Firefox, using "media\\:thumbnail" works fine to get an element with a namespace. This fails in IE 8, Safari for Windows and Safari for Mac and iPhone. Getting other elements without a namespace works fine in all browsers. I've searched the documentation and forums, and can't see that I am doing anything wrong. Here is a code snippet:

  1.     // Define the RSS feeds to load for thumbnail images
        var rssFeeds = new Array("photo/Favorites_2008/photos.rss",
                                "photo/Favorites_2009/photos.rss");
       
        // Load images from MRSS feeds
        function loadImages() {
            // Loop through all RSS feed URLs
            $.each(rssFeeds, function(key, value) {
                // Make an AJAX call to get the RSS feed
                $.ajax({url: value,
                    dataType: "xml",
                    async: false,
                    error: function(reqObject, textStatus, errorThrown) {
                            console.log("AJAX Error: " + textStatus + " - " + errorThrown);
                        },
                    success: function(xml, textStatus) {
                        // The RSS is Yahoo MRSS - get the thumbnails
                        // xmlns:media="http://search.yahoo.com/mrss"
                        console.log("AJAX Request Success");
                        // This find expression works in Firefox, but not IE or Safari
                        $(xml).find('media\\:thumbnail').each(function () {
                        // $(xml).find("title").each(function () {
                            // Add the thumbnail URL to the image array
                            favImages.push($(this).attr("url"));
                            // console.log("Added Image: " + $(this).attr("url"));
                        });
                    }
                });
            });



























The RSS feed is here:
http://www.shawnstepper.com/photo/Favorites_2008/photos.rss

The tag in question:
  1. <media:thumbnail url="http://www.shawnstepper.com/photo/Favorites_2008/tn/IMG_1001.jpg" />
The docs say to use a double backslash, but it doesn't work in all browsers. Any help would be greatly appreciated!