User exit or BADI for PGI with blank movement type

Hello,

   Am looking for a BADI or user exit which can throw a pop message based on certain checks. The BADI LE_SHP_GOODSMOVEMENT doesn't help because it is not called if the movement type is blank on the delivery (a particular delivery item category in our case).

   USER_EXIT_SAVE_DOCUMENT_PREPARE cannot be used as it is called in update task(?) and can interfere with rest of the processing.

   So which user exit or BADI can I use. Pop message is required after hitting the PGI button on VL02N screen. Access to LIKP, LIPS, VBPA and VBUK is required inside the exit/BADI code for the validations.

Thanks,

Rajesh