This is my first post here and I am still learning too, but maybe my experience will help.
I bought one of these as well (ZG8101 EU). Got mine from Monoprice and at first I was having trouble with getting it to pair and recognize, but after trying different ways to pair it and discover it.... now it works.
Not completely sure how I got it working, but there is one thing specifically I did.
After it was discovered, I set it up as a "Sensor"
Then, when I went under the settings for "Associations", I put a "1" in the field for "add or remove a node in this group"
It now works and outputs an "On" or "1" when the Garage door is Open (Sensor is in the Horizontal position) and then outputs an "Off" or "0" when the Garage door is Closed (Sensor is in the Vertical Position).
My next step is going to try to use a Zwave Curtain Module and hook it up to the terminals on my garage door unit to try and open and close it.... (Not sure if it is possible, but remember reading about someone doing this).
Hope that helps.
Buzz