Change Price with BAPI_PO_CREATE

Hello, i am trying to create a purchase order using BAPI_PO_CREATE, everything is working fine except price modification. All positions are created with organization and warehouse, but the prices is not changed, it uses the list price.

The code i am using is as follows:

For the header:

MOVE: SY-DATUM TO PO_HEADER-DOC_DATE,

'ZREN' TO PO_HEADER-DOC_TYPE,

'F' TO PO_HEADER-DOC_CAT,

P_DIVI TO PO_HEADER-PURCH_ORG,

'10' TO PO_HEADER-PUR_GROUP,

WERKS TO PO_HEADER-SUPPL_PLNT,

'0000000001' TO PO_HEADER-VENDOR,

V_PEDIDO TO PO_HEADER-PO_NUMBER.

For the positions:

MOVE: V_PEDIDO TO PO_ITEMS-PO_NUMBER,

V_POS+4(6) TO PO_ITEMS-PO_ITEM,

I_ARCHIVO-PED_MAT TO PO_ITEMS-PUR_MAT,

WERKS TO PO_ITEMS-PLANT,

LGORT TO PO_ITEMS-STORE_LOC,

PO_ITEMS-NET_PRICE = V_PRECIO.

PO_ITEMS-DISP_QUAN = V_CANTIDAD.

APPEND PO_ITEMS.

MOVE: V_POS+4(6) TO PO_ITEM_SCHEDULES-PO_ITEM,

SY-DATUM TO PO_ITEM_SCHEDULES-DELIV_DATE.

PO_ITEM_SCHEDULES-QUANTITY = I_ARCHIVO-CANTIDAD.

APPEND PO_ITEM_SCHEDULES.

Any clues as to why the price in my table isn't used? I get no error message, it just doesn't work.

Any help would be highly appreciated.

Rgds.

-- David