Freight not to be debited to customer receivables account

Dear all,

How can we configure this (seemingly simple) pricing scenario :-

I have a frieght condition to calculate freight say ZFRT = $ 20, which is credited to a Freight account in the billing document.

Now, we dont want this freight amount to be recovered from the Customer, rather it should be debited to an expense account in the invoice.

Kindly suggest.

Your answers would be thankfully acknowledged.

shalini.