All our web service test clients use a simple authentication. We would need to create a token authentication. It's actually supported by web service but no client and token administration has been created.
=> There has to be a form in Moodle somewhere - there you have to create token specific for content and web service and then you will get a list of URLS with your token in it - exactly like Google calendard UI

Specification: http://docs.moodle.org/en/Development:External_services_security#Random_all-time_valid_token