Alternatively you can bring up the console and type
set oppass1 "<password>"
set oppass1level #
Youll probably want to set oppass1level to 150 if you use this method, this will allow you to manipulate your server as you wish.
This appears at the bottom of the server.cfg file if you wish to take that route (suggested).
The only downside is that youll have to do this every time you open DP.
Just to clarify, if you choose to edit the server.cfg file then you will have to type "exec server.cfg" in the console everytime you open DP.