Automatically Create a Purchase Order from Purchase Requisition

Hi, i would want to automatically create a Purchase Order from an Approved Purchase Requisition.

Here's the details:

I have Items under VENDOR A that already as a price setup in a custom lookup table.

example:

Item	Vendor	Price
Item A	VENDOR A	1
Item B	VENDOR A	2
Item C	VENDOR A	3

When User creates a Purchase Requisition like below:

PR Line NUm	Item	Price
1	ITEM A	0
2	ITEM B	0
3	ITEM X	0
4	ITEM Y	0

Once it's approved, i want a Purchase Order to be automatically created like below:

PO Line Num	item	Vendor	price
1	ITEM A	VENDOR A	1
2	ITEM B	VENDOR A