Exit or BADI for while accounting document generating from VF01

Hi folks,

           I need an exit or badi which triggers while generating accounting document from VF01. My requirement is we need to capture condition value while saving billing document in VF01 and update it in a custom table only when accounting document is generating. I tried the exits 'EXIT_SAPLV60B_004' and 'EXIT_SAPLV60B_001' but not helpful. Is there any way that fulfills my requirement. Pls suggest.

Thanks,

Shyam.