I have been using a FGK-101 with the external temperature probe. I am using the the Native Fibaro Door/Window Sensor 2 driver. I can add this to the discussion.
1] The probe must be installed before including the device.
2] The instructions for a factory rest differ from what I have read here.
The key here is both TMP buttons.
I leave it to you to figure out how to press 2 buttons and insert the battery at the same time. 
I used this reference:
My biggest complaint with it is it uses ER14250 ½ AA 3.6v battery.
Can't find any brand named replacement battery that ship in factory packaging. I am leery of batteries that come in a plastic zip bag. For this reason I will not buy any device that requires one of those batteries.
