What I have been able to do in order to have a cool signature, is to go to the this site
www.mylivesignature.com/ and create your signature, then have it generate an HTML code. Copy that code and paste it some place where you can access it easily. (I put it in my One Note program from Microsoft Office) and after you have typed your post, go to the Image Link icon above it is a square with a chain link on it (6th from the right side above the smiley faces) and click on that. It will open a box where you can paste a link to an image. Paste the HTML code link to your signature in that box, and your signature should come up.
It is a few extra steps, not as nice as just having it be there any time you post, and you have to remember to insert the image, but it does work. That is the only way I have been able to find to add a cool signature on this new forum. I wish there was a way to just add it to the profile and have it be there with out all the extra steps.