ME_GUI_PO_CUST is not populating while and running and saving

Hi!

I've implemented badi ME_GUI_PO_CUST for adding additional subscreen to the line item level. My customer fields are in EKPO table. customer fields are visible in ME21n transaction. when I try to fill in values to the my customer fields and save. it gives a message saying No Data changed. looks like my customer fields are not identified by the program/ screen. Also my customer fields are not displaying any values from the table.

I've implemented my badi as in the sample code..help need in this.

thanks!