Hi,
Basically, Task Management allows you to create the task specifying some existing wsdl and execute this task. Depending on wsdl you may provide custom parameters while creating the task.
You may find sample task "Get NS Registered Services" in "Console - Manage - Jobs and Tasks - Samples - Notification Server - Get NS Registered Services".
To create new web-service task you need to right-click to any mode on Jobs-and-Tasks page, select New -> Task, find "Call web service" or "Call web-service on server" type of task in the left tree, load existing wsdl and press OK.
Thank you,
Alex.