JBC BT-2BQA soldering station sleep mode trigger?!

[Neshco]

I have this station and because of its position on the bench, and because the iron holder is permanently attached to the base, I bought this holder from Aliexpress to bypass the problem.
But, it turn out that sleep function when rest in it does not work.
I have tried to approach to the ring of the iron with strong magnet to try to trigger it, then I tried to approach it with some metal (I dont have anything ring-like to stick the iron in it) but nothing worked so far.
How this station trigger the sleep mode? 

[Krotow]

Look like my AiXun T3A. Sleep mode triggers by electric contact with metallic ring around tip end of handle. Yours have metal cylinder with concentric rings here. Don't mistake, it isn't the ground, but a part of "switch". The holder opening must be connected with a single banana socket a back of station. I see the appropriate sockets at back site of that Ali Mechanic holder (nice one BTW) too. Try connect your holder to the station with a wire and banana plugs.

Also try to find out are the socket behind your station is the switch entry and not a ground socket. So most likely you must open your station at first to be sure.

[Neshco]

Thank you!
Just tested, bypassed the case of the holder and metal part on the station where the iron rest and it worked just fine.
I have checked continuity between the esd!? connector behind the station and the iron rest and there is no connection. So, yes, as you said, the metal of the rest is the part of the switch. Problem solved