Ah wait wait!
Never give up! 
I upgraded the firmware of the RaspBee.
Then I restarted the deconz container “et voilà” now I can se a channel and a network ID different from zero.
It is also chenged the way how the LED on the RaspBee linked.
Before I could see only a green LED flashing, now I can see a red LED fixed.
Next step? 
If it is working then the next step would be to add devices right?
Eureka!
It works now.
I paired the Xiaomi water device.
At the end of the procedure in HA i can see a new device called “Water 2” (I don’t know why “2” but it doesn’t matter).
During the paring process the green LED blinked (just for the records).
Glad to hear!
OK, I’m stil around experimenting…
I reinstalled my raspberry with the lite version of raspbian and I re-created my environment (quite easy with docker and git).
I can still see the RaspBee with a specific channel and device ID both in deCONZ and in HA.
This way however when I try to pair my water sensor I cannot see it in HA GUI.
The pairing process looks to be completed but in HA I can see the Phoscon-GW and the Daylight sensor only.
@robban Any idea about taht?
If the device is properly added to deconz. And the connection between hass and deconz is correct. You should see it.
If you increase logging following the guidelines of the component documentation, can you see the sensor in the deconz responses?
Log didn’t tell me anything useful.
Nothing appeared (in th elog) when I tried to pair the sensor.
After to have tried lot of times I thought to reset to factory the RaspBee via deCONZ app under
Settings->Advanced settings
Then I restarted all the HA configuration of deCONZ integration and I paired again the senso et voilà it was appeared back again.
Just for the records…
