virtualization - How do I configure networking when using XEN on 12.04 Server

I'm following this guide, https://help.ubuntu.com/community/XenProposed, and I'd like to setup a static IP address, but I don't know how. I'm using 12.04 Server.

This is the step I'm having trouble at (I'm using eth1):

Edit /etc/network/interfaces, and make it look like this:
auto lo
iface lo inet loopback
auto xenbr0
iface xenbr0 inet dhcp
bridge_ports eth0
auto eth0
iface eth0 inet manual

I do this, and here is my output from ifconfig:

eth1      Link encap:Ethernet  HWaddr 00:17:a4:f8:79:20
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:478264 errors:0 dropped:0 overruns:0 frame:0
      TX packets:2895 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000
      RX bytes:46470058 (46.4 MB)  TX bytes:214620 (214.6 KB)
      Interrupt:17 Memory:fa000000-fa012800
lo        Link encap:Local Loopback
      inet addr:127.0.0.1  Mask:255.0.0.0
      inet6 addr: ::1/128 Scope:Host
      UP LOOPBACK RUNNING  MTU:16436  Metric:1
      RX packets:0 errors:0 dropped:0 overruns:0 frame:0
      TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:0
      RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
xenbr0    Link encap:Ethernet  HWaddr 00:17:a4:f8:79:20
      inet addr:192.168.1.122  Bcast:192.168.1.255  Mask:255.255.255.0
      inet6 addr: fe80::217:a4ff:fef8:7920/64 Scope:Link
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:471842 errors:0 dropped:0 overruns:0 frame:0
      TX packets:2795 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:0
      RX bytes:37005780 (37.0 MB)  TX bytes:182010 (182.0 KB)

So how do I give this system a static IP address? Sorry, I'm not that familiar with networking on Ubuntu.