Squid filters from router

Hi people, I'm using Squid+SquidGuard to filter the web content of a
private network, the topology that I built is:

+---------------+
| Internet |
+---------------+
| DHCP
+--------------------+ 200.*.*.*
| Proxy Squid |
+--------------------+ 192.168.0.1
| DHCP
+---------------+ 192.168.0.2
| Router |
+---------------+ 192.168.1.1
| DHCP
+-------------------+ 192.168.1.100/150
| Private Net |
+-------------------+

I hope that the figure was clear, what I get in the Squid's log is the
router's IP (192.168.0.2) but I would like to log the user's IP
(192.168.1.100/150)...

Thanks in advance..

Squid 2.6 STABLE1