Once you installed Rosettanet module, you can get the template for rosettanet business process.
Based on inbound or outbound, you can get the corresponding business process template and modify invoking service based on your requirement in the mapping service.
Rosettanet templated classififed in one action/two action.
One Action Intiator model (Outbound)
One Action Responder model (Inbound)
Two Action Intiator model (Outbound)
Two Action Responder model (Inbound)
Based on Your PIP(1 action/2 action) and Direction(Inbound/Outbound) take corresponding template and import into designer.
and modify the mapping service, Generate the model and enable the model in MWS.(Administrator section)
For more info, You can read the following doucment
webMethods_PIP_Tools_Installation_and_User’s_Guide_7_1.pdf
webMethods_RosettaNet_Module_Installation_and_User’s_Guide_7_1_Service_Pack_1.pdf