strange: with the english version (RDC102EN.dmg) you can type the following keys with CTRL+ALT as AltGr..
CTRL+ALT+ß for \
..Q for @
7..9 for {[]}
+ for ~
<> for ° and ^
for < and > you can use the windows keyboard tool -> Programm::Zubehör::Eingabehilfe::Bildschirmtastatur