Need to add it to your Steam name. Not the account name, the one your friends see. Open up your STEAM window click the settings button on the bottom and then the friends tab in there. and the ™ is (ALT+0153) using the numpad. Make sure numlock is on.
EDIT. I failed. Noticed you are CSS. Yeah just do it manually in the game. Although not a bad idea to add to Steam name so we can find you to put on friends list easier. Sorry for the mix up.