HTTP Receiver

Has anyone done any interfaces that receive HL7 messages via an HTTP POST? I have recently been involved in a project and the only way the client can send is via an HTTP POST. I was able to us the IHB with the java sample program to validate sending messages this way between my workstation and Cloverleaf. However, when the client trys with their software they get this error “CORE 029 An Action parameter must be specified”.