There are a few options
1. You can cut it up and use it as a stuffer, probably not what you want as this won’t retain the little space at all unless thickness is the appeal to you, its also pretty messy.
2. You can follow Cottontail’s [URL="http://www.adisc.org/forum/showthread.php/83319-How-To-Make-Diaper-Extenders”]Diaper Extender tutorial[/URL] (there also is some company making them professionally but I can’t for the life of me remember what they are called and google is not being helpful)
3.there are specially made diapers designed to mimick baby diapers like preschool
4.You can buy a modified one off ebay, the quality can vary greatly from seller to seller, so beware if doing that