WCF large size request data handling asynchronously

Question

I have a self hosted WCF service for handling HTTP POST request.
My WCF service method will handle 2 types of request (1. getting data, 2. Do some action with given data).
My scenario :
1. Started Action request with large amount of data. : during the starting of that action do some processing. 2. client reads some results. 3. sending the remaining data for the previous action.




I implemented this using 'TcpListener' it is working.
Problem: when i try to implement this scenario using WCF, i have got the 'Bad request' during the first action request.

Any help/guidance would be great as I'm really stuck on this.