Hello, Appy!
You dont need to recompile navboot to change menu language. Change module name in Lng_Hollands to Lng_Deutsch (I mean not renaming file, but changing module name directly in module at address 58h (add one 00 byte because "Lng_Hollands is one byte longer, than Lng_Deutsch)), edit module CRC, delete Deutsch module from navboot and paste your module. Thats it. If you cant understand my bad english, i can do it for you, if you want, and send you edited navboot.
My problem is bigger - there is no russian module (but i can make it) but i cant add russian to navboot fonts.