If you are willing to spend some time without those easy tools, you can just enter a new row in the items database, pick a high (unused) entrynumber and start playing with your tablestats (comparing tables with existing item's). Tools are GREAT, but if they don't match your table structure... this is the alternative.
When you've added new items and you can't seem to find them on your server, try emptying your cache folder in the WoW directory.