[libvirt] networking static ip address

Hi, we are using the 0.6.0 version and an Ubuntu guest os under KVM virtualization. We have tried several ways to assign a static ip address to the guest os eth0 device on boot, but we didn't success. Is there any easy way to do it? We are trying to have a guest with the ip 192.168.0.1 in the eth0 device, enslaved to the br0 bridge on the host machine, which seems to be a pretty easy setup to test. When the guest OS is booted, the eth0 device exists, but is not up, and doesn't have the IP. Regards, Francisco.