User Exit or BADI for VF04

Hi All,

I want to use a BADI or user exit for billing.

My requirement is to summarize two line items with specific GL accounts into one line item.I tried with the following BADI's. EXIT_XFMPR1_001 and AC_DOCUMENT.But both GL accounts and amount fields are not available together in any of the internal tables within these BADI's.Can any one suggest me a solution?This is a bit urgent.

Thanks in advance,

Soumya.