[solved] Cannot get service reference for transformation service of type JSONPATH

I’m struggling with this error.
I already followed advice from other topics.
Transformation service is installed via PaperUI and active.

210 | Active | 80 | 0.9.0.b1 | Eclipse SmartHome JSonPath Transformation Service
from addons.cfg

A comma-separated list of transformation services to install (e.g. “map,jsonpath”)

transformation = map,jsonpath
Usage of JSONPATH transform is in binding rule of items, like this:
Number Temperature_Outside “Außentemperatur [%.2f °C]” (Weather_Chart) {mqtt="<[mosquitto:/sensors/temperature/outside:state:JSONPATH($.temp)]"}

What else am i supposed to do?
Found solution why it was not working.
I had to name the broker to mosquitto in /etc/openhab2/services/mqtt.cfg to match it to the binding name in the item.
Now the state of items is updated from JSONPATH.