TF2 Engineer: How to build a Level 3 Mini Sentry

To build a lvl 3 mini sentry, you must first create a normal sentry and upgrade it to level 3. Then switch from your wrench to gunslinger. Pick up the lvl 3 sentry and go to the ressuply cabinet. Place down the sentry. Pick it up again and place it down again. Then it will be a lvl 3 mini sentry! I do not own team fortress 2 or valve or steam or Windows Movie maker or FRAPS in anyway.