Why no interface mapping?

Hi Xier,

Secnario as following:

1. JDBC sender send message to BPM.

2. BPM call Sync ABAP Proxy

3. BPM get proxy response

4. BPM use JDBC receiver write data back to DB.

So we need to define interface Determination for step 1.

we input Inbound Interface, but the interface mapping is optional, which show "Not Specified" in Receiver determination.

My question is why here don't need to input interface mapping, this interface mapping should transform JDBC sender interface structure to BPM's abstract interface structure. Why it's not mandatory?