We have updated the Custom Spray Logo guide on the site with the added parts for how to make one for Team Fortress 2. You can grab the below Spray which is our new logo from the download page now!

To add it to the game you need to add it in CS:S or HL2:DM and then move the .vtf file to the same folder structure under the "team fortress 2" folder. As it wont add it by the in-game option yet as its broke for TF2 until Valve fix it!