"Script Mode" language setup

I would like to use Scrivener in English language, because its way easier to understand and to use tutorials for learning. But I would like to write in German language. My problem is, that in “Script Mode” the Auto Complete Feature is always working in the Scrivener language and can not be set not a different one. Is this my fault and is there any way to solve? I can add German as spell checking , so far so good, but for Scriptwriting there is no option I found, to set up Script Mode language differently then the overall program language. Can you help me, please ? thank you