It looks as though it may be the way the content was added originally that is causing the problems. When I view the source I see html and body tags around the content. I also see that the text is inside of a single td. I think it would be best to try and strip this down so that it only includes the content and not the extra table or any other formatting. I tried to do this on in the links you sent and it seems to work ok but you will need to update the formatting to make it fit like before.
I'm not sure why the style is being lost though after the information is loaded into the editor. I think this might have to do with some encoding that is occurring on the HTML Editor instance on your update page. What does the code for your html editor look like on this page? Also, when you edit the editor in the wizard what is shown for the default value and is there any formatting applied to this?