I would add two custom fields (in particular checkboxes) in vendor master by user exit.
The table where I would create an append (this is my idea but I'm not sure if it is right) and add these checkboxes is LFB1, the include is ZXF05U01.
I executed SE11 with table LFB1 and I browsed until the last entry, here when I click on modify button I can see the following:
The first field named .INCLUDE is editable but the others are not editable.
So do I have to add my new fields in the above INCLUDE or in the APPEND ?