You should *literally* just right-click over the word "MY IMPALA" in my last post, select Copy, and then paste that into your Signature.
At first I tried copying from my pro-touring.com signature line for about 30 minutes.
Then I got smarter and looked at this sites page for a similar reference. (ie. where a Hyperlink exists under a common text name).
I saw "Private Messages" up in the upper-right hand side of the screen and knew it was doing what you wanted to do.
Most browsers have a function either in the right-click menu when you hover over a link, or in the pull-down menu's at the top that let you see the HTML source code going on 'in the background'. Of course, it looks like a bunch of gobbly-gook to any normal person but when you study/look at it, you can see the pattern of things develop enough that you get a very very rudimentary understanding.
Under that link "Private Messages" on everyones page, using one of the methods above, you can see the underlying code is <a href=/www.impalas.net/forums/21-site-discussion/"private.php">Private Messages</a>
Luckily I had seen the pre-pending and ending of the < and >. I've seen the use in fonts and colors and things as a /a.
As in, the a is the beginning of a string of codes, and the /a indicates the end of them. It's like a wrapper.
Looking at the string above, it wasn't too hard to know/test that we replace the word "Private Messages" with "MY IMPALA", and that we replace "private.php" with your link.
I've spent 28 yrs in networking, so I see this HTML stuff from time to time and once used Microsoft FrontPage to make a personal website. (a 10 yr old could have done it, lol) So, point is, I'm not completely unfamiliar with it. Troubleshooting web-access issues and building networks is what I do. I have to work with various application people a lot when they think the network is causing them an issue.