Not internally in The Bat, as far as I know.

You can use filter actions to save the attachments (or the whole message) and then use an external action to edit the saved file, but I don't think there's a way to then replace the message.html attachment with the edited version...

Maybe you could extract the attachments to a folder, then run an external action to edit the message.html there, then use the "Create a formatted message" filter action to create a duplicate of the original message (with attachments stripped), and use a macro in the formatted message to (re)attach the edited attachments. I've never tried anything like this and I'm not confident that it will work, but it might be worth a try.

(to edit the html file externally, you could use a batch-capable text manipulation tool. You can probably find a suitable one in this review of such utilities: https://www.smashingmagazine.com/2009/04/25-text-batch-processing-tools-reviewed/ )


Well, if it is a common problem, maybe you could submit this issue to Ritlabs and ask if they could work around it in their HTML renderer? That way we all benefit!