Wordpress Import and Archive Issues

I recently migrated from Movable Type to Wordpress. You can see the final product here: [login to view URL] I was able to import all of my old posts from Movable Type, and they show up as normal in the Wordpress admin area. However, all of my archives continue to remain the old posts, even when I intentionally publish to the same archive URL. By way of example, here is a post concerning the iPhone 3G: [login to view URL] As you can see, it is formatted with the old template. I have imported this post into Wordpress, and then re-published to that very same URL, but the old post continues to remain (it won't show changes to the temaplate or text). Moreover, when you click on any given month in the archives in the sidebar, it also takes you to the old archives. I want to republish all of these imported posts in the new Wordpress template on top of the old ones.