If you need to enable SSL in ProFTPD, try this out:
<IfModule mod_tls.c>
TLSEngine on
TLSRequired off
TLSRSACertificateFile /etc/httpd/conf/ssl.crt/server.crt
TLSRSACertificateKeyFile /etc/httpd/conf/ssl.key/server.key
TLSVerifyClient off
</IfModule>
