The reason HiJack isn't able to read the config.ini when the player is renamed is that it check's for the name of the process that tries to read config.ini and only reads it itself if that name is the name of the player binary.
Solution: Don't rename the player binary, but move it to a different directory. After that, your script needs to chdir to that directory and start the player from there.
Other solution: Rename/replace the init script instead of the player app. The script doesn't do very complicated things anyway, just mounts the partitions, starts the player app in a loop. In that loop, it also starts a shell of the player exits with a certain return/exit level. (See the developer section on riocar.org for more details).

cu,
sven