The driver is working with on/off but isn't always reporting power as it should. Turns out that the outlet sometimes reports power together with current (amps) but as an additional attribute embedded into the call. Never seen this before but i suspect it is to save some bandwidth on the zigbee mesh...
I have a draft running locally which seems to be working really good. Currently on a work trip so expect the new (actually working) version to be uploaded and shared here at the end of the week!