You must create a service interaction for each service operation in a business process. A service interaction is created automatically when a service is added to a project but can also be created manually. When a service is added to the project, the service interaction that is created automatically has the same name as the service but has an .iface extension instead of a .wsdl extension.
If a service contains only one operation, you can use the service interaction that is created automatically when the service is defined or brought into the Navigator. Otherwise, you must create additional service interactions manually, which allows you to use one of multiple schema (operations) from the same WSDL file.
Create a service interaction using the Service Interaction Creation Wizard.
To manually add a Service Interaction:
Highlight Services
in the Orchestration Navigator.
The file you create saves into this folder by default.
To create a service interaction, do one of the following:
From the main menu bar, select File>New>Service Interaction.
In the Orchestration Navigator, right-click to open the shortcut menu and select New>Service Interaction.
From the toolbar, select the down arrow at the right of the New Wizard icon, then select Service Interaction.
From the
toolbar, New Wizard 
, then select Service Interaction.
Follow the instructions in the Service Interaction Creation Wizard.
When you click Finish,
a new service interaction file with an .iface extension displays in the
Orchestration Navigator.
This iface file contains the same information as a file created using
the Service Wizard but not adding an operation.
Work with this Service Interaction file the same way you would an automatically created .iface file.
After you create a service interaction, specify the operation it will invoke. Open the Service Interaction Editor and drag a service from the project onto the editor. After you select the operation for the service interaction, extract the schema for the operation inputs and outputs.
The next task in creating a Service Interaction is Adding an Operation.
You can use the operation that defaults into the Service Interaction file when the service is automatically created, specify a different operation as described in step 2, or add an operation to a manually created Service Interaction.
If you are adding an operation to a Service Interaction, the next step in creating a Service Interaction is Extracting a Schema.