MRP: PR to PO conversion

Hi Experts,

MRP has generated PR's. I want to convert it to PO. I double click on the PR in the stock requirement list. It takes me to the "Additional data for MRP element" screen. Then I click the "Convert PR to PO" tab; ME21N screen opens up & header level data is copied over; but the item details of the PR is not copied over.

can anyone suggest why this is happening?

Then I put in th PR number manually, in the item level details. After this all PR details gets copied over to PO.

I would like all the PR details to be copied to PO automatically.

Thanks in advance.

Regards

Jack