How to handle Rebates and returns in Lockbox

Hi,

Our customer will be sending us the lockbox payments in EDI 820 format. The customer might send rebates and returns in the lockbox file with their own transaction numbers. They might send in the returns even before they send the product back to us and before we enter a credit memo. They will get to take rebates also, which they send in the file with their own number. Is there any way to handle these transactions with Auto lockbox.

Thanks,

Haritha