[EXIM] X-Envelope-To Problem

First off, I've searched the last six months of the archives or so and some of the docs and haven't found any mention of the problem I'm having....

My company has a multi-drop mailbox at our ISP. They're running Exim 1.73. I'm running FetchMail on our end to retrieve mail from the ISP multi-drop and then redirect to the local MDA. My FetchMail configuration works perfectly.... I know this because everything worked fine before my ISP switched to Exim.....

The problem I'm having is that Exim isn't formating "X-Envelope-To:" properly. I've narrowed it down to the following: If an incoming mail is addressed to one person, then "X-Envelope-To:" is set to that person's address. If the message has multiple recipients, then Exim is setting "X-Envelope-To:" to the address of the multi-drop mailbox account rather than the intended recipients. Thus, FetchMail reports errors on my end and delivers the mail to "postmaster" because it can't resolve any local names from the incoming message.

I've talked to my ISP about this and all he could tell me was that "X-Envelope-To:" wasn't a standard header field and that it wasn't up to him to provide support for it. However, other mail servers I've used (smail, zmailer, Exchange) handle this just fine.... I'd rather not change ISP's because of their choice of mail server software, so...

Can you provide any ideas on why this is happening and/or what can be done to "fix" it? I'd really appreciate being able to relay this information to my ISP if it's available.

Thanks in advance,
Kevin Traas