Need help getting gamercard into signature!

So I'm trying to get my gamercard into my signature, and xbox.com had a tutorial on how to do so.

http://www.xbox.com/en-US/MyXbox/embedgamercard.htm

Unfortunately I can't get it to work. When I follow the instructions, when I hit apply changes on the preferences page, it shows my gamercard. But, when I check my forum posts it just says "Insert Gamertag Here Too"!? I looked at the example on the webpage, and I did it correctly, just isn't working for some reason.

How did you guys do it?

Go to www.mygamercard.net type in your Gamertag once you did,go a little bit down then click on Forum Image.Then Copy the URL then paste that on the little tree picture next to the smiley face on the forum section on the prefs.