Can I Backup Directly to FTP?

I'm trying to backup my server to an FTP site but when I configure the offsite copy and enter my FTP details it wont allow me to continue without adding a local or network destination. I have also tried adding a local drive but when the backup runs it doesn't give the option to use the offsite destination and tries to backup to the local drive.

If it's not possible to backup to FTP, what does the FTP option offer?

Thanks,

LJAC