The latest firmware for the F3 was just released a few days ago, and it adds a great new option. Version 1.40, which can be download here, adds S-Log into the Picture Profile menu of the camera. This allows anyone to turn on S-Log without the RGB key, although you still need the key for 4:4:4 output.
Having S-Log in the profiles menu allows adjustment to the other camera settings such as black level, color, and white balance. I have put together an S-log profile that matches the normal S-log mode and also a modified file that combines the S-log gamma mode with color and black levels. You can download the files individually here (S-log and AB-Slog) or my full camera settings here, which contain both files and updated scene files as well. Watch my video above to learn more.