coupon discount for each item added when multiples of the same item are added to the cart

Hi
How do we set a coupon to apply the discount per item if the same item is ordered multiple times ie at the moment the coupon applies a discount to the first item added to the cart but we would like the discount to apply 2 times if 2 of the product is added to the cart.
Thanks
Felicity

When editing the coupon in the value field, set the drop down to 'amount per item' instead of 'amount'