:) I have this phone on my desk.
There is no way to disable the use of DND on this phone....short of using a screwdriver to rip out the softkey button.
You may be able to use the web interface to send a html form submit code, to turn it back on either periodically or programatically.
attached is the html code used for submitting configuration changes to the phone....you can check it out... though i'm not sure how you would accomplish it, i'm sure someone who is a decent web programmer could figure it out.
