Credit Management

Hi Experts

I am posting received payments from customers through down payments(F-29) and normal payments(F-02).

I want to enter credit control area in the customer line item manually at the time of payment posting which is already picking from customer master assignments and not editable.

We are using three credit control in one company code.

Please advise how can i make this field editable(BSEG-KKBER).

kuldeep Dubey