Back-to-Back synchronous calls in PI 7.31(AEX)

Hi

Below is a requirement in PI 7.31 (SP05) - AEX. Need design suggestions.

Sender: Thirdparty Web-UI application.

Receiver: SAP-ECC

1. UI places work order synchronous request to PI

2. PI calls standard ABAP proxy1 and receives response1

3. PI to use the response1 and make a call to another standard ABAP proxy2

4. Response from ABAP proxy2 need to be sent back to UI.

Is there a way to fulfill this requirement with normal graphical mapping or should I use Process Orchestration (PO)?

Note:

• Two different ABAP proxies are to be used which are present in standard SWCV (ESA ECC-SE 6.05). Nothing to customize in ECC.
• PI to expose the wsdl for the sender system

Regards

Praveen.