How to use CSS - assigned in my email theme's .info file, but does not come in (I have all the extra modules)

I have tried to put the CSS in the HTML HEAD, a style block in htmlmail--htmlmail.tpl.php, and inline, but styling is not happing for H1s and the body (which has a background url/image). Any ideas of how to get this working?

I have a CSS defined in my custom email theme's .info:

stylesheets[all][] = style.css

I have tried this with the FUll HTML text format and one that I created for HTML Emails. The HTML email format has the following filters enabled:
* Emogrifier
* Convert all characters to US-ASCII
* Convert line breaks into HTML (i.e. <br> and <p>)
* Convert URLs into links
* Correct faulty and chopped off HTML
* Correct URLs with Pathologic

But my css file does not get attached