[otrs] Always html on posts

Hi all Doing a google I appear to have the reverse of what everyone else has. I can send html, but cant get it to send plain, even if the original customer request is in plain. Anything that leaves otrs is leaving in html format which is proving tricky because client mails systems sometimes goto the top on a reply, sometimes to the bottom. I have set everything I can see to plain, the otrs system is going through an exchange server but I cant see there being an issue there. Im sending via pop3. I must be missing a setting somewhere. Tim