Validate sold-to while creating sales order(VA01) on enter at screen 4001

Hello All,

I have a requirement where I need to validate sold-to and bill-to during VA01 w.r.t to customer order block. Can someone help me out with what BADI or Enhancement points can i do this..

Please note: I need the validation to be done on press of enter not only while saving.

PS: I have did some survey on SCN and found suggestions of enhancing LV09CF66 in formon_request_1000. But that will only help while i'm doing changes in VA02(Partners subscreen) but not for VA01 main screen.

Thanks in advance.

Regards,

Murthy