Just an FYI - you don't have to make new posts to view the changes to your signature. The forum does not save a history of signatures. It only shows the current one from your account. So, any post at all that displays your signature, will show your new signature as soon as you change it. All posts with your signature, always show the same signature - the current one. And if you remove your signature, it'll be gone from all your posts.
See this FAQ: https://www.wilderssecurity.com/faq.php?faq=wilders_custom_faqs#faq_wilders_using_forum