Here is a sound mod pack for 4.12. It covers most of the sounds. Open the archive and drop the files according to the folders names:
https://dl.dropboxusercontent.com/u/...12_csounds.rar
If I remember correctly, it was Jaffa's sounds, that I had to change a bit to run all with the new 4.12 feature. Could probably be better, but should be ok as it is.