Diagnosis
The business partner that calls TTE for tax calculation is assigned inthe TTE input document as "Own Business Partner". This business partnermust also be assigned a role for each item.
Example: When a sales order is created for a sales organization, thissales organization appears for each item under the business partnerrole "Order Acceptance" (code OA).

Procedure
CRM Order: Contact system administrator.
In the Simulation Tool:
Go to the Input Document.
Choose the relevant item.
Choose ItemBProle.
Maintain a role for the own BP ID.