You may not have to wait for long. Its quite an exciting improvement for openwebnet BUS item integration with Alexa.
I suggest you and anyone else interested in this development also ‘like’ his post 
While we wait for the Alexa skill developement here are some more details and examples that will give you an idea of upcoming possibilities for openwebnet items:
The first semantic extensions (coming soon) enable you to support utterances that use “open”, “close,” “raise,” and “lower” commands such as “Alexa, open the window” and “Alexa, lower the movie screen”. These new semantic extensions (coming soon) can be used to deliver natural control of devices such as projector screens, windows, water valves, closets, drawers, garage doors, gates, curtains, shades, blinds, awnings, and more.