ok figured it out and as always, facepalm solution.
I already had Qubino wallplugs working. They update significant power updates on the meter_watts channel. I copied those configuration to the Fibaro wallplugs. As the wattage on the meter_watts channel updated on polls to the Fibaro plugs, I thought this was the right channel. But after turning on zwave addon debugging, I found out that the events are broadcasted on the sensor_power channel.
thanks for looking into it.