Hi,
From MM point of view, you have to configure the account assignment category correctly (in OME9)to receive stock to project stock while doing GR against PO.
Also, in the material master accounting 1 view, maintain the valuation class for project stock.
Now, for PS configuration details, refer the wiki doc: Step by step configuration for Valuated Project stock - ERP Operations - SCN Wiki
Regards,
AKPT