The issue is that the integration isn’t fully formed (not a criticism btw) – what you need is a Chromecast Audio – the round puck which you can use as a media player – you connect it to the Line IN on the NL/ML Converter (you’ll need a 3.5mm to phono cable) and then you can play the media in two steps in the automation.
Firstly in the automation get the chrome cast to Play Media (there you can select the source) – this will then start streaming to the NL/ML Converter. Then as a second step in the automation, get the Beosound 1 to play the Line IN
I’m assuming you have a ML Gateway…
