When I use TLMDMapiSendMail with Thunderbird, the HTML body I compose internally shows up as HTML in the Thunderbird compose window as expected. However, this is not the case with Outlook 365. It shows up as plain text (complete with all the HTML markup making it basically unreadable by the user). I have confirmed that Outlook is set to compose email in HTML. Any idea what might be wrong or how to trick Outlook?