"I've got this road that customers use to drive back and forth in their cars. We'd like to offer boat access using the same road . . ." HTTP and FTP are two completely different protocols needing completely different servers.

As was said, install Apache. With the right configuration (and possibly some scripting) you may even can get it to coexist along with things your ftp daemon does like custom per-directory banners (look for README.html in the mod_dir documentation).