BTW, after considering the potential complexity handling inputs of greater depth than list_of_lists, or more complex outputs, I think the next addition to TWiST will be <ws>operation. This will allow the developer direct access to writing the 'Invoke' command for the operation, which takes an inputXMLNS (where to find the input document) and fills an outputXMLNS (with the return document), and returns a reference to the documentElement. You could use this, for instance, to send all the data for an invoice and process the different complexTypes involved in a single transaction. (You can do this now by writing a proc and setting a variable pointing to it, but not using the TWiST API.)
