Hello, there is a lot known of the graveyard. Willem Tiemens (he died in 2007) wrote a book of it (Ehrenfriedhof Zypendaal te Schaarsbergen). It is in dutch but a very good site.
There is a lot more to find on the internet. There is nothing more to findout over there because everything is allready done.
I lived 20years close to there and know a lot of the surrounding aerea.

Greetings, piet