You should be able to edit your signature. Follow the menu selections, first click on Welcome – Log in, then Update Forum Info, then Edit, then Account. A box will be down the page a bit for you to enter your signature info. Then all the way at the bottom, hit save. You should be all set.
Wow! I didn’t think anyone read this forum any more. I haven’t tried uploading my sig as a image. This forum appears dead so it probably doesn’t matter. I come here for updates because I don’t have Facebook, but it looks like no one maintains the forum.