Defining Field Relationships 
You establish the field relationships between the project and the SAP system.
The source fields and the structure relationships between the project and the SAP system must have been defined.
From the list of steps, choose Maintain Field Mapping and Conversion Rules. A dialog box is displayed.
Choose Change.
Position the cursor on the appropriate SAP field.
Choose Assign Source Field. The Assign Source Field dialog box appears.
Select the corresponding source field. The system displays this field as source field now and defaults a field-related 1:1 processing (Move) of data.
Note
You can assign multiple source fields to an SAP field. However, data can only be processed by means of a rule that you create yourself. The predefined rules only support 1:1 relationships.