Synchronous RFC call in BPM

Hi all,

My scenario is:

1. Asynchronous web service call (SOAP -> XI)

2. Synchronous RFC call (XI -> RFC)

3. Another synchronous RFC call (XI -> RFC)

4. Asynchronous reply (XI -> SOAP)

In BPM I only can add the needed message containers for my synchronous calls after creating redundant asynchronous abstract message interfaces for the in/output messages. I have already created all needed synchronous interfaces.

Is there another possibility to create my request/response message containers in BPM than to bloat the whole scenario by adding these asynchronous interfaces?

If not do I have to do any additional interface mapping again?

Which interfaces do I have to reference in ID?

Thanks in advance!

Denis