null endpoints are not ignored by v3

The following command should create a single endpoint on v3 with a interface="public" and url="http://localhost:5000/"

$ keystone --debug --os-token=ADMIN --os-endpoint=http://localhost:35357/v2.0/ endpoint-create --region=north --service-id=239ff97ce7a14e2b92b7a513d1bb243f --publicurl=http://localhost:5000/
REQ: curl -i http://localhost:35357/v2.0/endpoints -X POST -H "User-Agent: python-keystoneclient" -H "Content-Type: application/json" -H "X-Auth-Token: ADMIN"
REQ BODY: {"endpoint": {"adminurl": null, "service_id": "239ff97ce7a14e2b92b7a513d1bb243f", "region": "north", "internalurl": null, "publicurl": "http://localhost:5000/"}}

RESP: [200] {'date': 'Fri, 08 Mar 2013 14:44:05 GMT', 'content-type': 'application/json', 'content-length': '204', 'vary': 'X-Auth-Token'}
RESP BODY: {"endpoint": {"adminurl": null, "region": "north", "internalurl": null, "service_id": "239ff97ce7a14e2b92b7a513d1bb243f", "id": "8e4785365bb84db2a00611d37f1ec522", "publicurl": "http://localhost:5000/"}}

+-------------+----------------------------------+
| Property | Value |
+-------------+----------------------------------+
| adminurl | |
| id | 8e4785365bb84db2a00611d37f1ec522 |
| internalurl | |
| publicurl | http://localhost:5000/ |
| region | north |
| service_id | 239ff97ce7a14e2b92b7a513d1bb243f |
+-------------+----------------------------------+

Instead, v3 returns the expected endpoint with null 'internalurl' and 'adminurl' attributes.

GET http://localhost:35357/v3/endpoints
X-Auth-Token: ADMIN

200 OK
Status: 200
Content-Length: 1506
Content-Location: http://localhost:35357/v3/endpoints
Vary: X-Auth-Token
Date: Fri, 08 Mar 2013 14:47:20 GMT
Content-Type: application/json

{
  "endpoints": [

    ...

    {
      "links": {
        "self": "http://localhost:5000/v3/endpoints/663d7b416f894741ae5957af68898a3e"
      },
      "adminurl": null,
      "region": "north",
      "legacy_endpoint_id": "8e4785365bb84db2a00611d37f1ec522",
      "url": "http://localhost:5000/",
      "id": "663d7b416f894741ae5957af68898a3e",
      "interface": "public",
      "service_id": "239ff97ce7a14e2b92b7a513d1bb243f",
      "internalurl": null
    }
  ],
  "links": {
    "self": "http://localhost:5000/v3/endpoints",
    "next": null,
    "previous": null
  }
}