Question about Outlook Express

Yes, that's right, I want to turn this OFF or edit it so that read receipts go to the correct email address. I know what you're thinking, that you can't even use read receipts in MS Outlook for Mac. But I have been, although by accident. This is what happened in my case:

Years ago when I had MS Entourage I set it up to ask for a read receipt when I sent emails. I did this by doing the following steps:

1. In Entourage I selected "Tools." and then "Accounts."

2. I selected the "Mail" tab and selected the account I wanted to use read receipts with by double-clicking on the account name.

3. I then selected the "Options" tab.

4. And, in the box labeled "Header," I entered "Disposition-Notification-To" and typed my email address into the "Value" box. 

5. After clicking "OK", Entourage was set up to request read receipts.

When I purchased Office 2011 for Mac, and imported my Entourage accounts etc into Outlook, it also copied this setting for me. This was fine - it just kept requesting read-receipts and that was good.

HOWEVER, the email account I was using is now no longer active and what I'm finding is that whenever I send an email, that the recipients whose computers are actually trying to send a read receipt, are returning them an error message because the email it's trying to send the read receipt to an email address that can't be resolved.

So, how do I now change this in MS Outlook? I need to either remove the "Disposition-Notification-To" setting, or change it so that it goes to my current email address.

Thanks for any help. It will be very much appreciated!

Joe.