I've got good news and bad news!
The good news is that I figured out how to do what you are looking for.
The bad news is that you're going to have to get rid of Disqus. Not sure how attached you are but it doesn't work with it.
1) Make sure you have created a Facebook app for your blog. If you've created a welcome page then you probably had to create one. If you don't have one yet then you're going to have to get one sooner or later. There are some great blogs that will help you step by step.
2) Download and install Simple Facebook Connect
3) Fill in your app key and fan page ID (this is the long number that used to be at the end of your Facebook URL before you got 25 likes.
4) Allow to publish posts to Facebook
5) Allow integrate FB comments
6) Deactivate Disqus
7) Publish a post. It will automatically show up on your fan page wall. No need to wait for the feed to refresh. Then a comment from the FB wall will come back to your blog.
Sweet!
Here are screen shots. I'm about to delete the tests.