Jippi, now i have it, it works!!!

I have to work with the GET command…
like this rule:

IF $thermostat-flur-unten.temperatureSetpoint changes
THEN execute “curl --silent -X GET --header “Content-Type:application/json” --user “user:PW” http://192.168.49.6:8083/api/device/thermostat-flur-unten/changeTemperatureTo?temperatureSetpoint=$thermostat-flur-unten.temperatureSetpoint > /dev/null”

thank´s all for the help!