Running R47031/R47071 - Trying to process using Customer/Supplier Item Number (CITM)

Hello - we are setting up the process in our JDE 9.1 to process ASN's from one of our suppliers.  Within the EDI 856 details, the supplier is sending their part number.  This is being mapped to the I record of the F47032 record in the CITM field.  Every time I try to run the R47031, the error I receive on the R47071 shows  Error # 143J - Item number not on purchase order.  The item on the report shows the supplier part number with a / in front of it and the supplier number is set up in F4104