@h8r:
TCP LAN net 21 (FTP) * 21 (FTP) *
Even tried with OPT1, but doesn't work. I followed this advice here http://doc.pfsense.org/index.php/Multi-Wan/Load-Balancing#FTP.2FNAT-Reflection_Workaround
You quite the right source. just add the rule like described there at the very top of your rules. The rule you created won't help as FTP is not only port 21. Delete this one, setup the rule like described in the docs and reset states (diagnostics>states, reset states) to make sure there are no old states from previous connection attempts.