Tax code PO using purchase category R12

We have used the manual Ref. Oracle E-Business Tax – A Purchasing Perspective (White paper, Oct 2007)

Setup tax using non-inventory based is working if we manually choose product classification in “Manage Tax” on the Purchase Order. There’s a need to link product classification to the purchasing categories for automatic default the correct tax rate.

When using inventory-based product fiscal classification, everything works as normal, and the tax code is automatically selected by the tax rules linked to the Purchase Category. The user don’t need to enter the form for “Manage Tax” on the Purchase Order. This functionality is needed also for non-inventory based since the customer isn’t using items.