How to add body content to RFx Bid invitaton mail?

Hi experts,

We are sending Bid invitation mail to bidders with a pdf attachment created via adobe form conversion (through BBP_BID_INV_ADB). Everything is ok about the attachment and subject but we need to add some custom text to the mail body which we could not manage to do. Does anybody have any idea to solve this issue?

Regards;

Murat Kaya