REST

What is the format returned from the services. Here is my request and response.  I can't figure out what the format is

REQUEST

POST https://dev-pc:9355/ServiceBusDefaultNamespace/horsefarmtracker/Subscriptions/SubAllMessages/messages/head?timeout=10 HTTP/1.1
Authorization: WRAP access_token="Audience=ServiceBusDefaultNamespace&ExpiresOn=1354284713&Issuer=ServiceBusDefaultNamespace&Upn=Dev&Role=%3aDev%2cNone%2cEveryone%2cHelpLibraryUpdaters%2cHomeUsers%2cWindowsFabricAdministrators%2cWindowsFabricAllowedUsers%2cAdministrators%2cUsers%2cNETWORK%2cAuthenticated+Users%2cThis+Organization%2cNTLM+Authentication&HMACSHA256=MxtVMofe9iGggjeKE96NVxnLsknIpFXM4k5acTk%2fkzw%3d"
Host: dev-pc:9355
Content-Length: 0
Accept: application/atom+xml;type=entry;charset=utf-8

RESPONSE

HTTP/1.1 201 Created
Content-Type: application/xml; charset=utf-8
Location: https://dev-pc:9355/ServiceBusDefaultNamespace/horsefarmtracker/subscriptions/SubAllMessages/messages/1/1602b636-79b1-4f69-9591-4e2a3b3a242f
Server: Microsoft-HTTPAPI/2.0
BrokerProperties: {"DeliveryCount":5,"LockToken":"1602b636-79b1-4f69-9591-4e2a3b3a242f","LockedUntilUtc":"Fri, 30 Nov 2012 14:07:52 GMT","MessageId":"1af4078e8166493c870b8171191b2ed2","SequenceNumber":1,"TimeToLive":922337203685.47754}
HorseId: 1
DOB: "Sun, 01 Jan 2012 05:00:00 GMT"
Date: Fri, 30 Nov 2012 14:06:52 GMT
Content-Length: 0