If you go to the Edit Profile link in the User CP (or on the left when you're looking at your PM's), it'll take you to a screen where you can put your TL in your avatar space. It'll be the little CML link under your av and CAG name.
Worst case, you could look for your info on the Members page, and search for your TL.
The only TL's that get deleted are those created by people who make them in locations other than the Trading Forum before they're able to (30 days), or when specifically requested by the OP of the thread.