Thanks for the reply David. What if there is no CUSTNUM in the import file, but that customer does exist in the MOM database already? Will MOM just create it as a new account, even if the billing info matches an account already present?

Let me ask another question, which might make the need of the first one null and void. Is the CUSTNUM only needed if the billing and shipping information isn't present in the imported file? Or does the CUSTNUM field serve another purpose as well?

I have a client using OSCommerce for their web ordering and MOM for their order management. They were previously using MIVA for web ordering, and in the MIVA export/MOM import process were somehow able to compare the customers from their web orders with the existing customers in the MOM database and assign the CUSTNUM field for repeat customers. Does anyone know how this can be done? I have the MOM import file being created correctly, and the only problem my client has with it is that it doesn't assign the customer number, which means it duplicates customers who have ordered before. Any help or insight would be greatly appreciated.