This is a very late reply, but just want to share the process of setting up all associated RFCs with EWA config, as well as important in the functioning of the system:
SAPOSS – created after configuration in transaction OSS1.
SAP-OSS – created after S-User ID is maintained in Global Settings -> Connection to SAP in transaction DSWP / SOLUTION_MANAGER
SAPNET_RFC – created by SDCC -> Maintenance -> Refresh -> Session overview
SDCC_OSS - created initially when you activate SDCCN.
SAPNET_RTCC – created by SE38 -> RTCCTOOL -> list -> Refresh from SAPNet