I've been writing an application for the company I work for, and when sending a HTML formatted body to QMail it's sending out to external mailboxes fine but loses all formatting when sent internally. I've looked at the actual file in the Maildir folder on the server and the formatting is on the email, is there some very specific combination of headers that I need to pass it other than:
Mime-Version: 1.0 Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit
And if so, why would it work when going to other email providers?