Your blog is behaving as designed.
By default, the page with the embedded blog will scroll so that the top of the blog will be at the top of the window. You do not have enough content in your blog to see the full effect, so it does, indeed, appear centred.
To change this behaviour see the help page at:
http://x6.nabble.com/help/Answer.jtp?id=48
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.