Modification of SAPMV45A Screen 4440

Hi experts,

I have some trouble with a extension of SAP program SAPMV45A and screen 4440.

Thes task was to extend the sales overview part of transaction (VA01, VA02 and VA03) with the field VBKD-ZLSCH (payment method).

So I modifcated the screen 4440 and add the necessary field with reference to the DDIC.

Furhermore I implemented a user exit/enhancment to set the field active (active = 1, invisible = 0).

My problem is, that if I execute the transaction I can not see the new field.

I don't know why...

Some facts beside:

- If I execute the modifacted screen directly in test mode it works. I can see the new field and the right position

- The "other way" works. If I use the enhancement implementation to disable a field, the field will not shown at the screen

So what I am doing wrong? Is there something additional to activate or customize?

Furthermore I would like to add a own search help to this field at the screen. The search help exit for the standard search help is already used by SAP standard. How can I do that?

Right now, my idear was to enhance the "standard search help exit".

Regards

Christian