The official version of WinSCP is meanwhile 4.1 beta, the portable version is still 4.0.7. At winscp.net you only can get the German language file for 4.1. So average users of the current portable version don't have the chance to localize this application.
To avoid such difficulties in the future: Is it possible to use the "WinSCP Multilanguage installation package" from winscp.net as the base for the development of the next portable version? This would help all non-English users.