FTP Speed Issue Through Dual Wan

[bgbearcatfan]

Hello all,

I have a question regards ftp speeds through a dual wan environment.
On the server, we are using a non standard command port, and a specified range for passive more for external clients.
There are NO initial connection issues, or problems with disconnections, etc.  There is simply a speed issue.  On our dual wan box, we have all of our ftp traffic forced through the opt2 interface (WAN2).  When clients connect they are receiving download speeds between 20-30KB/s.  We had a test box setup, WITHOUT a dual wan environment, just a simple 1 wan, 1 lan interface.  When they connect through the test box, they are getting normal speeds of around 100KB/s.  I know ftp isn't supported on dual wan, but i was hoping that was only limited to problems connecting to the server (through port 21, and open range for passive mode).  Is this a known issue with utilizing ftp over dual wan, or is something just completely bojanked with my setup?

Version 1.2-RC1
built on Sat Jul 21 13:47:02 EDT 2007