OK, I got it to work! Was a firewall issue. 
Works ok, takes 5-10 seconds at first connection, but still, no big improvement on upload speed (starts at 20MB/s, then drops at about 7-8 
).
I am thinking about my setup, it`s a raid1 config, on a Serveraid m1015 controller, with write cache disabled (just to be safe). I have to 2.5 inch standard IBM server hdd, 500GB.
At this speed, it takes forever to upload a backup, or to restore a machine.
Anywayz, your guide works, I now have FTP on ESXi 5. 
PS: running on gigabit network, from the storage server I can copy with reasonable speeds.