Two questions:
1. When I select to delete "On Mailbox & Handheld" it only deletes from Handheld.
2. Can I stop the BB from sending a "your message was delivered to recepient" notification to my Outlook when I respond to an email from the device?
* Also are you selecting multiple emails? If so, try one at a time.
* Go to messages, then Options, then Email Settings and then under "Message Services" change to the email address you would like to update (if all, then you have to change this option for each email. If there are 3 emails, you have to do this three times.) You will have the following options in which you can choose 'No'