For those of you well versed in the ways of wsdl, you might be able to do this by hand. But if you want a little help you can generate sample xml from the wsdl/xsd you get from a service’s metadata. Using Add Service Reference in Visual Studio creates this metadata for you. When you add your service reference, if you expand the files that you got you will see a couple of schemas.
Now if you have a xsd in BizTalk Generating an instance of a schema is a very basic functionality for all developers. I’m not sure how it is for the pure .NET developers though, but there are ways (of which this is one) that does not include BizTalk tools that allows you to generate xml for pieces of a schema.
In your service reference locate the schema you want (hint: in the above image that would be item.xsd) and open it with the XML Editor (you could just as well open any other schema, it need not come from a service reference in a project). Then go for View – XML Schema Explorer.
Right clicking on the node you want (your response) you can then choose to Generate Sample XML.
Now I make no claim as to having used this extensively – I’m a BizTalk developer, and as such I’ve got other tools at hand. I’m sure it’s got it’s flaws, but hey – you can always do it by hand if you aren’t happy with the help you get.