fsbext - Rebuild only or can I also build fsb archive?

[Somalia]

Can I only rebuild the same files to the fsb I extracted before or can I also build multiple ogg or wav files into one fsb archive directly?
Correct me if I am wrong, but I suppose this is not possible?
But then - can I at least replace the music files I extracted before and then rebuild the old but modified fsb archive succesfully?
For example: In a simple rpg game I have three areas and three different pieces of music for each area, so the content of the fsb archive would be xxxx.ogg yyyy.ogg zzzz.ogg -
and I don't like soundtrack xxxx in the first area, but I really like the yyyy song so my plan would be to replace soundtrack xxxx with song yyyy from the second area.
I extract the fsb archive and then put yyyy.ogg to another folder and rename it to xxxx.ogg and then replace the old xxxx.ogg with the new xxxx song. Can I rebuild to fsb with fsbext although the content of the new fsb archive would be different?

[aluigi]

The rebuilding feature of fsbext works only with the original structure and files of the original archive, so you can't add new stuff.
Have you already considered and tested the official FMOD tools (sound bank)?

[Somalia]

Ah bummer! - fsbext can only work with identical file information for rebuild.
The plan was to simply extract all the encrypted files from fsb archive and then replace only a few files with my own files which would be not encrypted and then build a new fsb archive which includes the original encrypted files and the new files.