RE: 12 FG Fasst - programming an optical kill switch
You would go into the Linkage Menu and then the Function section. Assign the desired switch to channel 9. Rename the function in the "Function Name" section of the Linkage Menu. Then go into the Model Menu and the "AFR" section. You can adjust the throttle cut function's AFR there.
Please realize that your original post was after business hours on Friday. Of course we'd not be able to answer until today.