I have submitted a sitemap through the ping address http://www.bing.com/ping?sitemap=<encoded URL> both through my web application (when updates are made) and manually typing in the URL. When I typed in the URL manually, I received a message that my sitemap was submitted successfully. However, when I log in to my webmaster tools, it doesn't show an updated 'Last Submitted' date. Is this normal? Should it not show an updated submitted date when submitting a sitemap through ping URL?