Workflow.asmx AtlerTodo

I am working with Workflow.asmx in SP 2010.

For the most part I am having no issues, but I find it frustrating that Microsoft does not provide more information as far as the parameters required.  For example, I am trying to complete a ToDo task using the AlterToDo method. 

http://msdn.microsoft.com/en-us/library/websvcworkflow.workflow.altertodo(v=office.12).aspx

My question is what should the taskData parameter contain? 

All that is provided is "The server parses the <taskData> node into a hash table with a key for each <elementX> tag. The inner value of that tag is the value of the key in the hash table. The resulting hash table is passed to theAlterTask method as thehtData parameter."

I understand that it is a XmlNode, but what are the available option for <elementX> tag? Since there is no example as to what the elements should be, I am left to searching the internet for some examples, or using trial and error until I get it working.

Typical example of Microsoft 's poor documentation. 

The documentation for the List.asmx UpdateListItems method does provide an example for the updates parameter, again an XmlNode.

http://msdn.microsoft.com/en-us/library/lists.lists.updatelistitems(v=office.12).aspx

I suppose I could start there and through trial and error modify it until I get the results I need.

Bill Behning