You can already turn off the Message-ID substitution, with the downside that Gmail will not place the returned message in your Inbox (IIRC it does show as a second copy in your Sent folder). Or you can leave it on, with the downside that your user interface might have wanted to use the Message-ID for threading. I don't see that there's anything else?can do for you.
Shal
I don¡¯t (yet) use it, but Is that because gmail has an option to file replies with the original message? ?
I use a dinosaur 2003 Outlook and have that option turned on.?