Check Price and Availability: is BAdI a must to fetch customer?

Hi,

While running the app Check Price and Availability, the screen (see the attachment) displays. Do I have to implement the BAdI BADI_SRA016_USR_TO_CUSTOMER to fetch customers? At the current stage, the user's access to the customer list are not limited and all customers should be accessible. How can I configure it?

Best regards,

ts