How to create a bridge in Ubuntu 9
 

I have upgraded from Ubuntu 8 to Ubuntu 9 I had created a bridge using bridge-utils and editing the interfaces file using the following

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet manual

auto eth1
iface eth1 inet manual

auto br0
iface br0 inet dhcp
bridge_ports eth0 eth1

however this does not work with version 9 and the interfaces are now being reported as unmanaged and suggestions?