Use handling units for subcontracting

Hello Experts,

we are currently trying to improve our subcontracting process. The stock of material is provided to the vendor in boxes, he processes the articles and delivers them back to us in the same boxes.

To be able to identify the boxes when they come back, we want to use handling units.

When i tried to test this, i faced a problem in transaction VLMOVE. There is no handling unit process similar to movement type 541.

Is this a customizing issue or is it not allowed to use handling units for subcontracting?

Hope you can provide some information on this.

Kind regards

Mathias Baumhoff