Issue with STO

Hello All,

I am trying to create inter-plant scenario (STO between WS and WF company code.)

When I am creating SA I get an error "Customer 37403 does not exist(Please change entry in plant A)"

Supplying plant is B ie 9501 and receiving plant is A.

I have maintained shipping point for Plant A with customer 37403.

Customer also exists and I have checked in XD03 with vendor as my supplying plant (9501).

What else do I need to maintain.?

Thanks and Regards,

Forum Shah