In case you didn't know, Visual Studio ships a handy tool called WCFTestClient.exe that you should try. It's a great tool for discovering and testing WSDL operations without writing any code. You can view the request and response messages in a formatted view or in XML. For details, see WCF Test Client (WcfTestClient.exe). There is one catch… it is available only with Visual Studio 2008 SP1.
If you use the default Visual Studio install folder, you can find the tool in the C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\ folder.
After starting the WCF Test Client tool, click File->Add Service, and enter the endpoint address of the service you want to open. For a list of adCenter sandbox addresses, see Microsoft adCenter Web Services Addresses (when you play with this tool, make sure that you use the sandbox addresses and not the production addresses).
The left pane of the WCF Test Client main window lists all the available services, along with their respective endpoints and operations.
When you double-click on an operation in the left pane, the operation is opened in the right pane. The operation's tab shows the request and response properties in either a Formatted or XML view. When you click Formatted, you can enter arbitrary values for the properties to test the service. To send the request to the service, click Invoke.
There is one trick that is not documented or obvious when working with arrays. To specify an array in your request, enter length=n in the Value column, where n is the number of elements that you want in the array. You can then expand the list (click the + sign) to add the values of the array elements.
The following snippets show the progression.
Thanks and enjoy!