I had the same question. So I did some research.
When we look at the compatible data providers on the Bookmap website, Das Trader is not present :
https://bookmap.com/knowledgebase/docs/KB-IntroductionToBookmap-Connectivity#bookmap-compatible-market-data-providers
So, I conclude that no, it is not possible to connect Das Trader data service to Bookmap.
hope it help! If you ever find more information please share!