Disable certain changes in sales order after production order release

Question

We are in the MTO scenario and are also using variant configuration. The business requirement is that after a production order has been released (REL status) the preceding sales order item should be “locked” for certain changes. Such changes would include VC and some other fields (e.g. quantity and dates). Some minor changes like texts should still be allowed.
The best idea we could come up with is to put some validation in the sales order user exits, but there are some disadvantages. It seems kind of strange though that there would be no such functionality in standard SAP (e.g. some changes in the order can’t be made after a delivery has been created). Is there by chance anything in the configuration that we missed?
I found this old thread, but it still seems to require user exits. Unfortunately couldn't find anything specifically on the production order / SO integration.
Thank you!

Answer 1

Hi Jelena,
Try in the userexit MV45AFZZ
  (form userexit_field_modification)
Example:
select * from afpo where kdauf = vbap-vbeln
and   kdpos = vbap-posnr.        
if sy-subrc = 0.
select single * from aufk where aufnr = afpo-aufnr.
if aufk-loekz = ' '.                                 
select single * from jest where objnr = aufk-objnr
and   stat  = 'I0002''   
and   inact = ' '.
if sy-subrc = 0.
screen-input = 0'.
endif.
endif
endif.
endselect.
.H.Terras