Adding Reference details in EKPO table me21n

Hi Gurus,

My requirement is to store the reference PO details in custom field ZZREFBS and ZZREFPS of EKPO CI_EKPODB.

I have added the fields in CI_EKPODB and a new custom tab is added at item level using screen exit (screen 111) .

Now the problem is to be passing the values to these fields. When the user enters the reference PO details in the Item overview tale control, it gets refreshed immediately. And before it gets refreshed I need to save the values to the respective  line items.

Can you please guide me on how to achieve this.

Regards,

Suzie