Reporting on XML data that SSRS reads directly from SQLServer

In MS whitepaper

Reporting Services: Using XML and Web Service Data Sources

http://msdn.microsoft.com/en-us/library/aa964129(SQL.90).aspx

It says you can take XML from SqlServer, pass that as a parameter to a subreport, and (in vague language I don't understand or precise language I misunderstand) that the subreport will be able to report on the data.

So this potentially could eliminate the need to read from a web service or URL. 

This starts and bottom of page 9.

Can anyone show a simple example of how to include data from an SQL Server - I'm with the author up to and including step 5 of the procedure, I can get a hunk of XML back from the server.  Now how do I make a subreport use it?

Thanks