Sorry for my lack in reply.
I have moved away from OH for the moment.
Anyhow, I did some research earlier and concluded that I knew too little to find some good information by myself.
I used wireshark to find some package information but wireshark did not give much information, the gateway is talking to a cloud(outside IP) with mDNS, wireshark could not understand the package.
I purchased a CC2531 zigbee sniffer using with a TI sniffer SW I got the whole package from the zigbee sensor. I think the information might be used for something, but not quite sure.
Waiting for a program card for my CC2531 so I can install Contiki OS on it so my RPI can receive the packages.
If you guys want to have this working, please spend some time in looking into it. You might have some knowledge that I don't.