Drush destination command not recognising

Question

I'm able to see the destinations by using the 'bam-destinations' command and below is my script to get an entire site backup from a ftp destination (ID of this destination is 'ftp_destination' and I have entered ftp details through BAM module frontend).

drush archive-dump default http://www.example.com/ --destination=ftp_destination

For some reason it's not uploading in to the ftp location but just creates a backup called 'ftp_destination' in my local PC.

Thanks