If you used to use Classic, HTML wasn't allowed in sigs their either unless you modified your script to allow it. This is because of security reasons, allowing HTML can be a big problem if certain evil people know how to use it "properly". If you must have it, and trust your board members, you can prolly go to
www.threadsdev.com - they might have a mod for it already, or you might be able to convince someone to tell you how to enable it.
---Jamin