I have tried the suggestions already posted and I think the DNA might be different somehow. When I goto the menu >> settings >> account settings, there is no option to change the ringtone for that particular email account. You can only change the account name, your name, and update the password. Tapping Finish Setup only takes you back to settings.
In the menu, if you go to settings >> Notification settings, you can only turn on/off the notifications, sounds, and/or vibrate. There is no options to change the ringtone
Help
In the menu, if you go to settings >> Notification settings, you can only turn on/off the notifications, sounds, and/or vibrate. There is no options to change the ringtone

Help