During customer account creation in R12 could not find an option to search salesperson using salespe

During customer account creation in R12 could not find an option to search salesperson using salesperson number. This is under Account>Business Purpose> Details> Salesperson field. Only Name is available as search option. In 11i search can be performed using both Name and Number.

The navigation is: Customer Maintenance Manager (Responsibility in eBS)>Customers>Customer Search>Accounts>Account Sites>Business Purpose> Site Use Details.

Under this responsibility Salesperson is a field. My query is to find out if we can customize the LOV to have 2 options for Salesperson search, i.e.

Search By LOV

Name - Already exists

Number - We need to include.