ME_PROCESS_PO_CUST allows save in ME21n despite error message triggered

Question

Hello MM Experts,
We have a business requirement to prohibit the use of account assignment "A" (assets) on 2 particular document types that are used by departmental end users that should NOT be allowed to buy assets.  The purchase of assets is retricted to our centralized purchasing buyers who use a different document type. 
We recently upgraded to ECC 6.0 from 4.6c, so we want to try BADi ME_PROCESS_PO_CUST instead of a user exit.  We applied the BADi to ME21n and the developer referenced methods 'check' and 'save', as well as 'post' and 'close'. 
Our new error message is successfully triggered when a check is done in ME21n (error says "Account Assignment "A" is only valid for PO's and CSO's).  But, depending on the sequence of entry steps for required fields, when I use the save icon or do another check, the box "SAVE" or "EDIT" appears.  You can then save the order and by pass the error message. 
Other times, depending on a different sequence of entries in the ME21n screen, for the required fields, the correct box "HOLD" or "EDIT" appears and you cannot save the order with the incorrect account assignment A/asset (you can only correct it or hold it as a faulty order and correct later).
Thanks for any advice,
Suzanne

Answer 1

Dear Suzanna ,
In that case, you need to track all of the "action" or "button" in ME21N, you need to use "sy-ucomm" in the badi code to track all the check. like when you display a PO in ME23N than you switch to change mode, then the sy-ucomm = METOGG, and so on, tell the abaper to use sy-ucomm,there'll know about it.