How to save data within BAdI CUSTOMER_ADD_DATA in TA: XD01/XD01

Hi,

after I solved the problem to transport data from the subscreen to the BAdI CUSTOMER_ADD_DATA, I struggle with the problem to save them.

I appended two fields to KNVV, but after changing them and pressing the "SAVE"-button they won't be saved. Any idea?

Best Geert