I believe you can find some examples on the nwn vault, something called omega forge. If my mem is right. Here is the nwn vault link but I dont have the exact link to omega forge.
http://nwvault.ign.comyou can also get a example of how to do this from the nwn mods that came with your game. You can either beat the module and have them open in your toolset, or find them in your nwn folder and copy and paste them into your module folder.