Lookup value is not updated in the "ledgerjournaltranscustpaym" in d365

Hi,

I have lookup field for credit card type of create payment journal form.

I have a extension class for CustVendCreatePaymjournal class.I have selected the credit card type but lookup selected value is not updated in the “ledgerjournaltranscustpaym” form in Ax 7.someone help me.

How did you set the value?