BADI with Disput management

Hi Gurus ,

I am implementing a BADI in dispute management , In Dispute management in NOTES area , If its not having CLOSED REMARKS , After i clicked CONFIRM button i need to show an error , How can i get this , I am using SCMG_VLDT_BFR_STR_C this BADI and IF_EX_SCMG_VLDT_BFR_STR_C this Interface . Help me in this .

Thanks in advance ,

Saravana