Renaming car sounds

does anyone know if there's a way to rename car sounds correctly so they don't replace an already existing one? i've tried this before, renaming the sound then scripting it in through the use of car_tune and the results are either that the game crashes, or the sound doesn't play at all. this depends on the type though (engine or horn). if anyone could get back to me on this, that'd be excellent because i'm working on another vehicle project at the moment and i am going to have some custom sounds for it. thanks.

This is something i've also been having problems with and seeing as noone posted here.. *BUMP!*
Hopefully this helps us get noticed, hm?