I believe the reason you cant find it is because you are using burning crusade or higher. You would have to extract it from the file before they started to protect a majority of their files, which is a patch pre-bc. Luckily, I had this same type of issue, and installed WoW on my computer I bought after I quit WoW. Now I can extract both the newer files (on my computer I used to play WoW on) and the older protected files.
So, music for your support in my thread. I believe this is what you requested, if not, specify.
~Asomath