Open up your Command Line, cd to the directory you want to create the file in and run the following commands:
set fileName="switch_keys.reg"
echo Windows Registry Editor Version 5.00 > %fileName%
echo[ >> %fileName%
echo [C:\SYSTEM\CurrentControlSet\Control\Keyboard Layout] >> %fileName%
echo "Scancode Map"=hex:00,00,00,00,00,00,00,00,03,00,00,00,38,00,1d,00,1d,00,38,00,00,00,00,00 >> %fileName%