select Sales order number in Payment journal

HI All

How could we force the AX 2009 to attache the sales order number in the payment journal for the customer, that’s mean provide the abilty to user to select from the customer s’sales order numbers into the payment journal line

Thanks

In the settlement you can see the invoice number but not sales order number.

A sales order can have multiple number of invoices and payment can be against an invoice.

What makes you to have a sales order number there?