SOAP to HTTP synchronous

Hi guys,

I have the following scenario:

Sender system sends XML A over SOAP.

XI maps to A to B.request, sends it to receiver system over HTTP synchronously and receives an XML B.response.

XI maps B.response to C.request and sends it to receiver system again over HTTP synchronously, in order to get C.response.

Finally I have to publish this as a Web Service. in order for the sender system to invoke it.

I will definitely need a BPM.

I am a little bit consfused with the Message Interfaces and Message Mappings that I will use inside the BPM.

Can you help me on that please??

Evaggelos