stock trasfer setting

Dear gurus,

when i am doing transfer posting the system is giving following error

Purchase order 4500000314 does not contain items for a stock transfer

Message no. M7153

Diagnosis

The system did not find any item for a stock transfer in purchase order 4500000314.

Possible causes of error:

You have entered the wrong purchase order number.

The purchase order you have entered is not a stock transport order and the item category of the purchase order items is not U.

The purchase order you have entered is not a standard purchase order for cross-company-code stock transfers.

You can only post goods issues for stock transport orders belonging to this order type in the Sales and Distribution system (SD). You cannot enter the goods issue in Inventory Management.

Procedure

Check whether your input is correct.

Check whether the purchase order is a stock transport order with item type U or a inter-company-code stock transfer.

Perform function

If you have authorization, check in Customizing for Purchasing whether goods issues for stock transport orders in the plant with this purchasing document type are to be posted in the Shipping system or in Inventory Management. If a delivery type has been entered in the Customizing table, the goods issue takes place in the Shipping system.

In Customizing, choose:

Materials Management -> Purchasing -> Purchase Order -> Set Up Stock Transport Order.

i have created two plants A ( receiving), B ( supplying)

create vendor master for A taking B as a vendor,

pl guide

Vikas