Problems with VF04 VBRK-NETWR

I have aproblem creatinginvoices withVF04. Thesplitis donecorrectly,createsinvoiceswith the expected value, but when documents arerecorded, theVBRK-NETWR field inall documentsis thesame value and matches the valueofthelast bill.

It seems thatthe header dataofthe last invoiceit copiedallthe above.

Can anyone help?.

thank you very much