After spending long painful hours circumventing group security AND windows 2008 server Firewall, and setting up FIlezilla Server on an amazon EC2 instance with the correct settings (feeew !), I was finally able to connect to my FTP Server remotely. However, Filezilla kept taunting me by spitting a "Failed to retrieve directory listing" error.
After a couple of hours twisting each and every possible parameter on both server and client sides ( I tried every possible Active/Passive combination) I finally threw the towel and decided to put my last hopes on some alternative FTP client and pray. I Downloaded WinSPC and... Voilà !
I am finally a happy man after a spoiled sleepless night, but I am still frustrated because I still have no Idea of what got wrong.
Any suggestions are welcome.