If you want to use SAP GTS to place goods under special procedures, you have to define at least one customs ID with identical keys in both the SAP ECC or SAP S/4HANA feeder system and the SAP GTS system. The customs ID is the reference level for customs procedure-specific inventory management in SAP GTS.

In SAP GTS, you assign the customs ID to the foreign trade organization of the responsible company code. In the feeder system, you link the customs ID for customs warehousing and inward processing respectively to the storage locations whose stocks are in the customs warehouse and/or in inward processing. For outbound processing, the customs ID has to be assigned to the plant or plants that manage the provision stock of the subcontractors in third countries.
Note
The definition and assignment of customs IDs are described in detail in the Configuration Guide.In addition to the definition and the assignment of one or several customs ID or IDs, you have to flag all products that you want to place under a special procedure as relevant for this procedure. To do this, you can use the Manage Products app in the Product & Classification space on the Product page. In the product master record to be edited, choose the Special Customs Procedures tab to select the appropriate customs ID.
Once you have maintained the product master, you send this information to the feeder system. To do this, you can use the Redistribution: Products for Special Customs Procedures - Individual or Redistribution: Products for Special Customs Procedures - Mass Proc. transactions (transaction codes /SAPSLL/PR_DISTR_SG and /SAPSLL/PR_DISTR_MS). There is also an app for the individual transfer of information regarding special procedures to the feeder system (Distribute Product Data to Feeder System - Special Procedure).