EDIT:for your cbf problem:
It is the goal, that you put a
cbf file in addons, not a
folder.
You have to repack your changed files in a new cbf, dont replace any, that will result in a crash.
after you repacked your cbf, place it in vietcong/addons.
About removing sounds:for example, you want to remove all background sounds from a level.
Lets take the crickets from Halongport as example.
You open up Halong in the editor,
( using the duplicate function, or recent scenes)
You select the event that creates the sound.
( the purple piramids are events )
Then you select
Properties.You will see a number, that the sound event has.
Open up the Xsound.txt, located in various CBF files, and search
( control F ) for that value.
Then you will see, various soundfiles, either wav or ogg, are linked to that code.
That means, you have to change them all.
In the case of the crickets, there are about 3 wav files for every typ of cricket sound.
Just use your mind, it helped me to