I can get the install to execute but the command line argument is not being accepted by the setup.exe and hence it always runs in the default language.
Ok, c++ers, how come this does not work:
_spawnlp(_P_NOWAIT, ".\\SOMEDIR\\SETUP.EXE", szArgument, NULL)'
where szArgument is "-l0x0007"
(BTW, I can run "setup.exe -l0x0007" and it runs the correct language.)