Gateway load balance

[Raul I. Becette]

Hi all

First time posting.

I am a long time Linux user (desktop and server) and started with 
FreeBSD a year ago.
Thanks to the book Absolute FreeBSD 2nd Edition I learned a lot about 
the OS and how to configure different services I used in Linux (Slackware).

My post is regarding something I couldn't find information on how to 
implement it. Here's the situation:

I had a proxy server (Squid + Dansguardian) under Slackware on the LAN 
which, via 'ip route' I make it use 3 gateways connected each one to an 
ADSL line and balance the requests.
Unfortunately my server crashed and I took the oportunity to install a 
new one under FreeBSD 7.0-RELEASE. Squid and Dansguardian are working 
fine. My problem is that I don't know how to make the server use the 
other 2 gateways I have left and balance the requests on all ADSL lines.

192.168.10.9/16                      proxy
192.168.10.2/16                      1st gateway (1 NIC to LAN - 2 NIC 
to ADSL modem)
192.168.30.100/16                 2nd gateway
192.168.30.1/16                      3rd gateway

I found it could be done with PF (also read most of The Book of PF) but 
I am quite lost about how to do it.

Any information would be greatly appreciated.

Thanks in advance

Raúl I. Becette