The app is wrapped by PhoneGap, so I have access to change the C#.
I know mailto body is sent as plain text. I've read that in OS3 a flag can be set in with the MailComposerViewController class to send html emails.
I don't mind exiting the app to send an email. I just wondered if I could change a little bit of #C so that my HTML5+JS app can use mailto to send rich emails, which seems less work than using the MailComposerViewController and getting it to talk to PhoneGap.