As there isn't any documentation on fst.bin, I have written one for those who want to know.
The fst.bin file is divided into 2 parts, 1st is file entries & 2nd is filenames
file entries
each file entry is a 0xC segment
(00) (filename offset 3Bytes) (offset>>2 4Bytes) (filesize 4Bytes)
(01)...