Undelete PO item with PR archived

Hello experts.

I need your experience in order to know how to reverse a PO item marked for deletion whose PR has been archived. When I try to reverse the deletion indicator in PO I receive error "06275 purchase requisition does not exist".

I found in another discussion a solution but I tried with no success (http://scn.sap.com/thread/456498)

Could any of you give a solution so I can undelete PO item?? It is necessary to cancel an invoice urgently. It should have a way... 😕

Many thanks in advance and best regards.