Description field on the PO Header

Hi

Our PR's are converted into a PO using the Create PO Document workflow. The issue is that the description of the requisition header is not transferred on the PO Description header.

I'd like to know how can we map the requisition header to be populated to the PO header when the PO Create document workflow is creating the PO? .e.g same way that the Requisition line 1 description get populated to

PO line 1 description field? .

Thanks

Tumi