I'm sorry, I didn't make it very clear did I?
Basically, anything you change on the page http://forum.pokemon-world-online.net/usercp.php?action=editsig will only affect newer posts. So if you changed your settings to always include your signature, for example, older posts may still not include it unless you then edit them. However, for posts that DO show them, the avatar and signature will be the same everywhere - you will always see the latest ones you set.