NB Purchase Order instead of STO

We'd like to use a NB purchase order with vendor in order move finished goods from one plant in a company code to another plant under a different company, we need to use the NB PO with a vendor to record the dollars and charge. The only item I'm stuck on is auto assigning a specific plant and storage location to the material on the PO that carries over to the NLCC delivery, so far the storage location is plant when I create the NLCC delivery. Can somebody clue me in on where to maintain the vendor/plant/storage location data, when I use vendor 300XXX I want it to fill from a particular plant and storage location.

Many thanks!