STO of Special stock E // way to controll EKPO-UMSOK

Hello together,

I am facing following issue.

We want to use stock transfer order (special stock =E) for transfer of the goods from plant A to plant B. (same company code)

It works fine, if the MARC-SBDKZ maintained as blank in plant A. Unfortunately we cannot use blank in plant A. The possibility to use consumption indicator E is not an option for us because of some controlling issues.

Is there any other way to control EKPO-UMSOK depends of the business scenario? We tried Badi

ME_PROCESS_PO_CUST. We are not able to change UMSOK field, since UMSOK is not changeable.

It is a field of the table MEPOITEM_TECH.

Is there another possibility?

I would appreciate any ideas

Vitali