To add a REG_MULTI_SZ multi-line registry value, i can do
reg.exe ADD \"HKLM\\path\\to\\registry\\key\" /v RegistryValue /t REG_MULTI_SZ /d \"abc\\0def\\0\"
Try this:
@reg.exe add "HKCU\Software\Wirkomatron" /v "MySoftware" /d "Software1"\0"Software2"\0"Software3"\0 /t REG_MULTI_SZ /f
And now you can do it with Batch script propertly.