How Partner profile determine in EDI Outbound processing for Sales Order.

Hello Experts,

I have some knowledge of Idoc but I am not able to understand how system pick Partner profile in EDI Outbound processing for Sales Order??

I understand T-code VOE4 (Table: EDPAR) is to map the Sold-to party and Ship-to party for the given External partner number (Partner profile) in case of Incoming IDoc BUT in case of outbound How system determine Partner profile ??

Is system use VOE4 for outbound Idoc processing as well ?? I dont think so .

Kindly give you precious suggestion.

Thanks,

Prashant Sharma