Add Magento Discount on simple products with custom options

General information for the business: We sell furniture online Description of requirements/functionality: We are using magento and have alot of simple products with custom options. The problem with using catalogue price rules is that it does not work correctly if a simple product has a custom option that changes the price. We need to modify the catalogue price rule so that it applies the discount after any custom options with or without prices have been chosen. Or create a new extension Specific technologies required: Magento Extra notes: