>Interesting ...
>
>First of all, I guess the extension must be HTM for .CreateMHTMLBody to work. (not terribly surprising).
>
>However, using this file, I still get the odd behaviors noted earlier.
>
>However, if I open Word and then re-save the file, it works just fine in my message.

The point here is that if you open it in Word, it will fill in the blanks for you and supply a lot of inline styling. Word is not something I'd call a neutral observer.

You should open your favorite web browser (and also the other browser, just to be sure) and drag-n-drop the file into each, then see the results. Or just open it in Notepad (or fox, with modify command) and see how it looks, is there any malformed HTML etc. If you have a real HTML editor with a validator, that'd be even better.