BetterThanLife posted a tutorial concerning custom interface screens.
This tutorial guides you through the creation of your own custom user interface screen for Neverwinter Nights 2. The screen is responsible for allowing the user to change their characters name. This is an illustrative example but you could easily extend it for a variety of other purposes. A sample module is included that allows you to ask a gnomish 'name changer' to change your name for you, this just shows one use of such a script and screen.
Download the zip file with the module showing how he did it from his site:
http://www.machinations.org/ChangeNameUserInterfaceTutorial.zip