ipAddress and privateIpAddress are missing from describeInstances

e.g. (using a local openstack instance):
<?xml version="1.0" ?><DescribeInstancesResponse xmlns="http://ec2.amazonaws.com/doc/2008-12-01/"><requestId>req-d579ea04-57c2-458d-ab97-a9fa0cbc60e8</requestId><reservationSet><item><ownerId>c0d2475ad0be46c9b132e256a3664389</ownerId><groupSet><item><groupId>juju-devstack</groupId></item><item><groupId>juju-devstack-0</groupId></item></groupSet><reservationId>r-6lmnvbj3</reservationId><instancesSet><item><placement><availabilityZone>nova</availabilityZone></placement><keyName/><instanceId>i-00000002</instanceId><instanceState><code>16</code><name>running</name></instanceState><publicDnsName/><imageId>ami-00000004</imageId><productCodesSet/><privateDnsName>server-2</privateDnsName><dnsName>server-2</dnsName><launchTime>2012-06-24T19:29:55.000Z</launchTime><amiLaunchIndex>0</amiLaunchIndex><rootDeviceName>/dev/vda</rootDeviceName><rootDeviceType>instance-store</rootDeviceType><ipAddress>10.0.0.3</ipAddress><instanceType>m1.small</instanceType><privateIpAddress>10.0.0.3</privateIpAddress></item></instancesSet></item></reservationSet></DescribeInstancesResponse>

the ips are present in the reservationset, but not in our Instance objects. AWS's tools report ip addresses as well, so I think either we used an old version of the schema initially, or $IDunno.