Occasional threading related need

Hello everyone,

Not surprisingly, I'm on several mailing lists, and because of the  
variety of email software out there, I often get a reply to a previous  
message, which does not thread.   The last few I've looked at turned  
out to be that way because the person replied to a digest.  He did a  
great job of editing down to only what he was replying to - but  
obviously the References: and In-reply-to: headers referenced the  
digest email, not the actual message he was replying to.

In the past, I have actually manually edited the email file to insert  
appropriate References: and In-reply-to: headers, but that is obviously  
subject to error.  Oddly, if I look at the list archives, all messages  
are correctly threaded.

Has anyone else noticed this, and are there any ideas on getting the  
threading "correct" in Balsa?  I don't think Balsa is doing anything  
wrong, I think the proper headers are not present, although the mailing  
list (pipermail, in this case?) seems to recognize the "References:"  
header as the digest, and so perhaps just threads by Subject?

Thanks for any suggestions.

Jack