Issue with header text in MIRO transaction

Hi team, requirement is send invoice date to other system using RFC. It's triggered when invoice created in MIRO. Issue is when user maintained header text for invoice in Note tab it's should send to RFC. But when controller comes to RFC header text not saved in STXH table so READ_TEXT function module doesn't captured header text. After completion of transaction only header text saved in STXH table. I am using invoice_update badi for send invoice date to other system. It's captured all the data but not header text. Can some one help on this.