I updated a website to 7.1 and activated the new url provider in web.config. All my urls come now without .aspx , thats fine.
But in sitemap.aspx, all the urls still have the .aspx ending ! Seems not a good idea to give google the wrong urls and then redirect them to the real thing.
Something else should be checked: I moved one page in the menu structure so the url changes. But in the sitemap, everything stays like it was before. Did you forget at the end to implement the new url provider in sitemap.aspx ?