When you are editing your signature, in the editor box there is a button that has a globe and "link" of chain. Click on it, and enter what you want the link to say and then the address. Hope this help ;-)
Copy the address (once you begin, you can't back out without canceling and starting over)
Above the message field are a line of Icons starting with B IU
Click the blue globe with chain underneath
Write your title in the box, paste address in the next box. Bingo.
.............................
D'oh. Gotta learn to type faster.