wM OMI service: omi.wm.is.userNotification.sendNotification

I’m working with Manager 6.5. The package WmOmiIS has a service called : omi.wm.is.userNotification.sendNotification
In the Manager Server Administrator’s guide, it’s written that The sendNotification service takes IData as the input data type. However, i didn’t find any input/output parameters when i tried to use this service.
So, while invoking this service, the following error occurs:
com.wm.app.b2b.server.ServiceException: Error: Service call does not have any messages at omi.wm.is.userNotification.sendNotification(userNotification.java:45)
I reloaded the package but it has not solved the problem. Plz suggest. Thanks