An alternate method to going into the CuteSoft files to add the new button would be to create a user control that wraps the CuteSoft component.  Just enter the code that loads the custom button (the code written by Adam and highlighted in yellow above) in the control's Page_Load method.  Also include the accompanying JavaScript functions in this control. 

Whenever I want to use the configuration of the CuteEditor that uses the custom button, I just drop the user control onto the page, and it loads the custom button for me without any additional code.  It might be a possible work around for your situation.