Davide,
as Obelix pointed out, you should code a program to become an FTP exit point.
In site
http://www.easy400.net you may find an utility, named SECTCP, which, besides optionally providing FTP and TELNET security, logs all FTP commands and provides interactive daily lists and statistics. After installing SECTCP, you may install its WEB interface, utility WSECTCP and browse FTP logs from your WEB browser.
All that was done through FTP exit points.
The utilities are open-source, are written in CL and ILE-RPG and you can customize them to your needs.