Populating XBLNR in the FP08 document

I have a CM posted with reference to an Invoice.

While reversing this CM using FP08, I want to copy the reference field of the CM into the reference field of RD.

I could not find any event where I can change the RD header data (DFKKKO-XBLNR)

Currently, the XBLNR comes blank in RD.

Is there a way we can achieve this?

Any pointers will he highly appreciated.

Thanks,