After a busy weekend I finally got a wizard working to help with the configuration of a SnippetCallback. In the latest build of Ajax Snippets there is now an option from the action list of a SnippetCallback on the designer named 'Configure...'.

After clicking this option a wizard will popup where an asmx file can be selected and a web method from this service.

One problem with this is that the web application must be compiled before the wizard can get access to the web service method list, the wizard basically pulls out web service type defined by the class attribute in the asmx file and tries to use Type.GetType() on it, if the web application is not compiled with asmx file then the methods do not show up in the wizards list, but I did stick in a red warning label under the drop-down-list if this happens.

The next step allows the mapping of controls to the selected web methods parameters.

The main benefit of the wizard is it avoids any mapping mistakes and typos, it could also do with a page to configure other options of a SnippetCallback but at least these two steps cover the main options.