Just came from an interesting discussion in the Adobe forums regarding proper HTML formatting for email. The issue there is the DW CS4 no longer supports deprecated HTML formatting (font tags, etc) only linked or inline CSS styles. Therefore, a properly formatted HTML email is impossible to create in DW4.
Many email clients simply won't properly render CSS styles.
So, while the integration of UE to DW for creating your email is nice, you have the same problem if you're using CS4. The tutorial actually mentions creating an absolute path to a linked stylesheet if you're not using inline styles.
This solution is a recipe for failure. Sorry!