Hi Saurabh,
It is just a normal web service which is published in the services registry. Any web service(with i/o parameters) can be imported into the BPM project and used in automated activities.
If you cannot find it anywhere, I suggest you use/create any EJB and create a WSDL out of it.
Note: You can also create synchronous/asynchronous WSDL from your BPM project:
