Hi,
We were also facing the same problem. Then what we have done is:
We have designed as code such that user should not be able to chnage the account assignment category in ME51N/ME52/ME53N/ ME54N.
You can implement the same in badi ME_PROCESS_REQ_CUST at item level. Contact your abaper.
mereq_item-knttp.
WHEN c_e.
WHEN OTHERS.
MESSAGE XXX.
Else, you can go for screen varient SHD0 to make Account assignment field as display. Try it in quality server.
Regards,
Priti.