How to post goods issue from project stock in outbound delivery from project stock

Dear all,

I want to post a goods issue from outbound delivery (OBD). I have available quantity in the project stock. I also entered the WBS number in the OBD.

But I get error M7 021 - Deficit of BA Unrestricted-use 2.000 KG : 2000006 5000 SIT 0000000035.

How to tell the system to use the project stock?

Best

Peter