Applying a Theme to Our Simplenews Emails

Written Steps
In this video, we will apply a theme to our newsletters.
This is a premium video series. You can buy it now for instant access.

In this video, we will apply a theme to our newsletters.
This is a premium video series. You can buy it now for instant access.
Comments
HTMLmail sees my theme but ignores my style.css file
Thank you very much for the tutorials, they are great! Unfortunately I am having some failure to launch...
I am working in Drupal 6 though as I am doing this for a client of ours who has a drupal 6 website and is happy with their current functionality...
I have done the following:
1. Created the theme with .info file, style.css file, page.tpl.php file and I have an images folder.
2. Took the htmlmail--simplenews.tpl.php file and copied it into my theme folder.
3. Assigned the theme in HTMLmail settings.
Is there anything I need to change in the htmlmail.tpl.php file? Please could you elaborate or point me in the right direction? I also want to add a custom footer and header... would I add that in the htmlmail-htmlmail.tpl.php file?
Made a typo error
Sorry in the first question it should be htmlmail--simplenews.tpl.php. :)