Here is a simple solution on passing the optional API parameters in the Employee Integration in SP04. The BAdi available for the same is only in SP06 and hence the solution given here is a simple workaround till the system is upgraded to SP06 level. Post upgrade, it is recommended to create an implementation of the BAdi.
There are several optional processing parameters that can control business logic when editing rows in the User entity. For example, the User entity allows you to change the manager for a user. When changing a user’s manager, you can tell the system how to handle any documents that may be in the user’s inbox. Documents include Performance Review Forms and 360’s.
SAP recommends to use the BAdi HRSFI_B_SFSF_API_PARAMETER for sending these parameters. But as per the note 1895092, it is required to upgrade to SP06 for this BAdi to be available.
Please get more details from the discussion Optional Business Processing Parameters in SF Employee Integration
The permanent solution is to upgrade to SP06 and implement the BAdi.
Alternatively, we can implement an implicit enhancement and pass the required parameters during the Employee integration in SP04.
Create an Implicit Enhancement in the standard object at the end of the method.
The name/value pairs of the processing parameters should be populated into the internal table rs_upsert_request-upsert_request-upsert-processing_param