You use this function to define customer-specific sourcing rules in addition to the standard ones to determine sources of supply in SAP Supplier Relationship Management (SAP SRM).

You implement customer-specific sourcing rules with Business Add-In Implement Sourcing Rules (/SAPPSSRM/SOS_BADI), which you can find in Customizing for SAP Supplier Relationship Management under  SRM Server Cross-Industry Functions Customer Enhancements (BAdIs) Sourcing Rules Implement Sourcing Rules . You can define sourcing rules either in ABAP or using Formula Builder. You can implement additional checks using criteria such as delivery priority and contract type and assign a message to be displayed in the Sourcing application. If you decide to use the Formula Builder, the parameters of the interface method are used as the available fields in Formula Builder.

To extend Formula Builder with user-defined functions, you must implement Business Add-In Appl. Specific Functions for Formula Builder Method Implem. (METH_FOBU_CONNECTOR) and define a new class. The related implementation is /SAPPSSRM/SOS_FOBU_I, the related implementing class /SAPPSSRM/CL_IM_SOS_FOBU_I.