Set homematic cover level to percentage position using emulated hue (with alexa)

I’m using emulated hue to switch my homematic actors and it works very good. The homematic covers are recognized as dimmable lights using the emulated hue component.

Whats working is to say “alexa turn on cover office” to open up the specified cover. Whats not working is to say “alexa set cover office to 50 percent” - alexa answers “the device cover office does not respond, please check the network connection”.

The use of homematic switch actors with alexa works flawless, because there are only the two states on/off.

Is it not possible to control the cover levels with the emulated hue bridge?

any ideas?