Copy Pricing COnditions from Shipment Cost do to Purchase Order

Hi:

How can I copy all freight conditions on shipment cost document to the Purchase order created.

e.g. In shipment cost document a\I have following pricing conditions.

ZFRT - Freight - $250.00

ZFCL-Fuel Chrg - $25

ZCLN-Cleaning Chrg - $30

Total = $305 on shipment cost

When Purchase order is generated automatically.

I want same conditions on Purchase order instead of gross amt PB00 of $305.

How can we copy conditions from Shipment cost doc to the Purchase order??