Punchout - BuyerPartID is not comming on payload (STAPLES)

Summary:

We have requested to implement Sourcing Master Items and Agreement Lines through Punchout. Accoding to the documentation attached, the item code will come on the payload on the tag BuyerPartID. But once we check the payload generated by STAPLES this tag is not appearing. only this information is on ItemID section:

<ItemID>
<SupplierPartID>24395089</SupplierPartID>
<SupplierPartAuxiliaryID>24395089</SupplierPartAuxiliaryID>
</ItemID>

Why BuyerPartID is not comming?

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):