Rfxtrx kaku (coco) dimmer not working, switches and cover does work

Hello people,

i am converting from Domoticz to home assistant. so i am a total newbie
i am running hassbian with HA 0.100.2.
i managed to get my Rfxcom transciever working for my switches and my Somfy shutters.
but i cannot get my dimmer to work. the dimmer is controlled by a remote with on,off buttons.
i can recieve the Id codes from the remote when i use the switch platform:
https://www.home-assistant.io/integrations/switch.rfxtrx/
but the light platform does nothing:
https://www.home-assistant.io/integrations/light.rfxtrx/
if i use the automatic_add: true, i recieve nothing.
i tried to use the ID of a switch to control the light integration. but this didn’t work.
what else can i try?