BCC: and CC: addressed e-mail not rec'd

Hello,

We download our e-mail from our ISP to our Exchange 5.5 (SP4) server.

It has come to our attention that whenever the address is in the BCC: or CC: field of the e-mail, it does not get distributed to that user. I can see the e-mail onthe ISP server and I can see it being downloaded. It disappears when it reaches the Exchange Server.

All e-mail addressed in the To: field is delivered correctly.

Is there a setting that controls this? Does anyone have any other ideas?

Thanks,

Marc