function RegWriteMultiStringValue(const RootKey: Integer; const SubKeyName, ValueName, Data: String): Boolean;
Writes the specified REG_MULTI_SZ-type registry value. Returns True if successful, False otherwise.
In a REG_MULTI_SZ-type value, each string is separated by a null character (#0).
begin
RegWriteMultiStringValue(HKEY_AUTO, 'Software\My Company\My Program',
'MultiStringTest', 'String1' + #0 + 'String2' + #0 + 'String3');
end;