How to map the "Supplier Text" field to a R/3 item text field (PReq)

Dear Experts,

how can i map the "Supplier Text" from my shopping cart to a certain item text in the Purchase Requisition (SRM 7.0, Classic Scenario)?

As per my understanding, the "text mapping for inbound and outbound texts"-table is mapping the "Internal note"-field in the shopping cart to a certail item text in an R/3 document.

But, where can i set up the same mapping for the "Supplier Text" shopping cart field?

Thank you very much.