Tax code determination in stock transfer order item

Dear all,

We are setting up the stock transfer order for 2 plants in the same company and the same country. In this case, no tax should ever apply.

Yet, when we are creating a stock transfer order between our two plants (9S01 to ZB01), tax code in item is mandatory, and never populated by default (Z11 is a copy of STO).

What we would like to do is to maintain a tax code somewhere, like we are used to for example in purchase info record for external procurement: we maintain the tax code at material / vendor / purch. org. level and the tax code is automatically populated when creating a new purchase order for external procurement. However, PIR will not be allowed for plants (only external vendors allowed).

If you could give me some advice on how to get this solved I would be grateful.

Kind regards,

Pierre