it wont support async, i mean you dont find any async interface in standard content.
step 1 : recruiting - you will send the position information from SAP to SF. this is part to of recruitment integration. After SF receives the positions, recruiting process will happen in SF.
step 2 : on boarding - once candidate is hired, their applications will be imported into SAP to create employees. here this is also synchronous scenario but data will be fetched from SAP.
each position will have unique guid. this will be used in both recruitment and onboarding integration. so while importing selected candidate, SAP will make a call to SF to get the list of candidates based on guid. due to this you dont need SF to SAP inbound.
if you download RDS document,it will have list of interfaces need to be configured for recruitment.
in my project i have used below interfaces for recruitment.
SFSFSessionHandlingLoginQueryResult_Out
SFSFSessionHandlingLoginQueryResult_In
SFSFSessionHandlingLogoutQueryResult_Out
SFSFSessionHandlingLogoutQueryResult_In
SFSFAPIDictionaryListSFObjectsResult_Out
SFSFAPIDictionaryListSFObjectsResult_In
SFSFAPIDictionaryDescribeSFObjectsExResult_Out
SFSFAPIDictionaryDescribeSFObjectsExResult_In
SFSFGenericUpsertRequestConfirmation_Out
SFSFGenericUpsertRequestConfirmation_In
you can get the use of each service by going through RDS document. GenericUpsertRequest is the one which is used to send the position information to SF.
channel configuration is same like as you do in login and logout.