Turn off HF on Futaba T7CAP - How to automaticaly turn off HF by train

[Pitlab]

Hi
Do You know how to automatically turn off the HF on Futaba T7CAP?
On it's older sister: Futaba T9CAP it works by simple shortcut between pins 4 and 5 on trainer socket, but on T7CAP this method doesent works.
Of course I can pull off the crystal...
I dont know how to think abiut it. Is this error or feature?!

[kiwi]