How can I send a read receipt when Send Read Receipt is set to no?

I have a user with a 9800. We just recently switched our E-mail provider from a POP to Exchange on Outlook365 (Online Web Application). The account on the blackberry is set up as an IMAP. He has his "Send Read Receipts" set to "No" on the OWA, his outlook in the office, and his BlackBerry. If he reads the E-mail on the Web portal or his outlook, it works fine - No read Receipt is sent. But if he reads an E-mail that has a read Receipt request on it on his Blackberry, the Read Receipt is being fired off. Any suggestions on what to try?