This is a quick fix to get the Leo in the Dog Fight mission of the demo to fight back.
Extract the zip, and you will get two files: demo.ca and demo.pd. Move the demo.ca file into the CACHE folder of your installation directory (e.g. C:/Program Files/Battlefront/T-72/CACHE), and move the demo.pd file into the DATA/scripts folder (e.g. C:/Program Files/Battlefront/T-72/DATA/scripts).
If it's the correct location you should be prompted if you really want to overwrite the existing file(s). Confirm with a yes (of course feel free to make backup copies of the older files first).
That's all! Now in the Dog Fight mission, the Leo should be firing back and moving.
Don't expect too much, though - the demo mission has never been scripted to let the Leo do much more than, well, fire and move a little; the idea being to create a fairly static situation in which you get a VERY first taste of maneuvering as well as are able to practice several approaches one on one.