How do I apply discount to the custom option

[ansonng]

I have applied discount for the view.phtml(product page) by modify the product.js and the Abstrast.php to apply discount for the custom option (ex. original : Red + 10$ ; discounted : Red + 5$ (50%)).

These works fine for now but once click on add to cart and redirect to the shopping cart, I realize it still on the old method which haven't apply the 50% discount for the custom option. 

My question is how can i modify my shopping cart as well? I know default.html can affect it's apperance and the Data.php somehow affect it's price out put. But I cannot find anything about the custom option for the shopping cart.

Images below is my example

 

[Brent W Peterson]

Your discount in the shopping cart will apply to the final price and not the actuall custom option. For example once you can't add an item to your cart until you set your custom option so once the item is in the cart the entire price will be affected by the custom option.

[petercool]

Hi Brent, I have TESTED the same issue, which is the custom option price will not effect by the discount.

Below are option at Menu: Promotion > Catalog Price Rules > (one of the promo) > Action

I have tested these option for "Enable Discount to Subproducts", but still unable to have discount on custom option.