PF ftp-proxy , transparent mode

[Marcos Biscaysaqu - Thepacific.net]

Hi there.
    Im running a Freebsd with PF and ftp-proxy . I have this redirection:

rdr on $int_if proto tcp from any to any port 21 -> 127.0.0.1 port 8021

the problem is when I connect to a ftp server on active mode the traffic 
is comming from the ftp-proxy on port 20 and not with the real ip of the 
ftp server, this create some problem on MAC OS machines.  should a 
"transparent option" or some way to make this work.  the ftp-proxy of 
freebsd has an option to setup the transparent mode but needs ipnat to 
work, but im using just pf.

any idea?
thanks !!

Marcos Biscaysaqu
Thepacific.net