Need to Trigger an IS service whenever a Fucntion Module get

Hi all

I have a requirement. I need to call a IS service whenever there a function module get executed in SAP and get the output of that function module in my IS service to further process it.

I have created a RFC listener notification which listens to that Function module,i have given the service to be invoked in that notification.But i am not able to figure out what document i will get in that service which will give me the output of that Function module.

When i created the RFC listener Notification two documents were created,whether Reply document will be the input parameter to my IS service to get the output of that Function mdule.

If i am wrong can some one explain me how i can achieve this thing…

waiting for prompt reply

Regards
Pankaj