Have you read news that gentoo developers have sent you?
eselect news read 2009-04-06-x_server-1_5
xorg-server 1.5 now have option to use hal to configure devices (in future xorg.conf will be not needed atall)
and by default looks for configuration options for devices in /etc/hal/
You can:
1. Disable new feature be adding
Option “AutoAddDevices” “false”
to your xorg.conf
2. Start using new features…
Make sure your xorg is compiled with hal and edev flags.
and copy following file
<?xml version="1.0" encoding="UTF-8"?>
<!--
Section "InputDevice"
Driver "evdev"
Option "XkbLayout" "ee"
EndSection
-->
<deviceinfo version="0.2">
<match key="info.capabilities" contains="input.keyboard">
<merge key="input.x11_options.XkbLayout" type="string">pl</merge>
</match>
</deviceinfo>
into /etc/hal/fdi/policy/10-xinput-configuration.fdi
More details here