The firing angle is, as it says, the firing angle. You can very well make it shoot straight up with that. The sound of the little bird passing over is a .wav file hidden in a .pff file where BHD is installed. You can use a pff extractor to examine them all.
The act of playing the wav file and creating the smoke is done using wac files. There's a tutorial on how to make your own wac files.
http://www.novahq.net/?show=utilitie...ew_files&id=11
It's near the bottom.