ftp masq on non standard ports not working

[Mike Egglestone <megglestone@heritage.sd57.bc.ca>]

Hi,

I just jumped into iptables. (sid with kernel 2.4.18)
phew!! what excitment
Anyway,

I have masquerading working from private ips so
that they can surf, but FTP is not working.
I had this similar problem with IPchains.
With IPChains, I would edit /etc/ipmasq/modules 
and unpound the ftp line there. 

Is there a new way to fix this with iptables?
and what if the ftp server is servicing on a port other than
the standard 21?

Thanks

Mike