SBS 2008, pop3 and invalid headers that are receipts

Hi..

I have been a bit perplexed and have had no luck searching for answers. I have been searching off and on since I installed new server in January.

We previously used sbs 2003 and the pop3 connector. I successfully received ndr, read and delivery receipts when requested through outlook (2003 or 2007) from a client computer.

In January we migrated to sbs 2008 and migrated our settings/mailboxes from sbs 2003. Now... I have read everywhere about invalid headers and them not being received by pop3 and having to go directly to isp's mailbox and clear these. Fine, understood. I have done that when it has occurred and reset my limits about receiving more than 5 of these. My problem is that ever since migration, when we request read receipts, delivery receipts or something is ndr we do not get them. They get stuck on the isp server and do not get picked up by sbs 2008 exchange 2007 sp 1/pop3. We have it configured to use pop3. (We do not want to receive the email directly) It thinks that these messages are invalid. I understand that not all servers that will necessarily send us the requested read receipt for example. However... I want to be able to see those that do come to us. This is for ease of mind of my users more than anything. I have explained that there is no guarantee and that the person receiving message doesn't even have to respond that they got it and delivery was just confirmation more or less that it left here. But, they got used to it on the older server and it gives them 'peace of mind' for whatever reason. I have turned off read receipts and delivery for now on individuals outlook but every few weeks they ask if I have resolved this. Now, when reading forums it sounds like this feature still works for other people on SBS 2008 so I am now not sure where to be looking as to why when it goes to pick up the messages from the ISP it leaves those behind.

Non delivery reports stuck look like this:
-----------------------------------------------------
Undelivered Mail Returned to Sender

From "Mail Delivery System" <MAILER->
To <>
Date 06/01/2010 02:37:46 PM
Attachments Delivery report.dat [ 387 B ], undefined 01.dat [ 2.32 KB ]



This is the mail system at host mf30.mfg.siteprotect.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system
----------------------------------------

Any help is appreciated.