FTP with virtual IP-Adress doesn't work

Hello,
I have a problem with Squid-2.1-PATCH2.
Our Proxy is running on a Linux-box (Kernel 2.0.32)
We have several virtaul IP-Adresses definded.
One of them for the Proxy.

Now I can't get a FTP-download.
The Control-Connection to the FTP-Port of the Server is ok and with the
right IP-Adress. The DATA-Connection is etablished on the first
IP-Adress of the Ethernet-Card, not on the virtal IP-Adress we
configured for the Proxy.
Now our Packet-Filter eats the DATA-Connection.
in squid.config we assigned the virtual IP-Adress to tcp_outgoing.
Could anyone help me ?

So long (Bis dann)
Elmar

-- 
Elmar Jansen                    Work:       e_jansen@krzn.de
KRZN                          
Kommunales Rechenzentrum Niederrhein  Tel: +49 2841 782 486