Sending Synchrously in BPM

Hi All,

I need a help on a BPM. I am using a RFC synchronous interface, so I have opened a Sync-Async Bridge and then I have a SEND Synchronous step. In the Receiver Determination, what should be my Sender Interface. The Business Service is the IP, but no Synchronous Interface appears in the list if Sender Interfaces. Can you please help me out here?

Thanks,

Geetha