for the blank ogg file , just record a blank wave file with wave lab for exemple and convert it to ogg with the oggenc (you can download it on vietcong customs, sgc base , pterodon site , vietcong coop site etc etc..). look at the exemples , you can also edit the .txt if you want to change the music , ingame voices etc in a map
edit : you maybe can find a tutorial topic on pimpcong site if it didn t got erased