Pulling simple products into cart from configurable

Question

I have a configurable product, where the simple products have different stats (i.e. some have no VAT), so when it comes to checkout, I need the simple products to be in the cart to show the differences.

Is there a way to pull the simple products from the Configurable when the customer adds the configurable item to the cart?

Additional info:
Magento ver: 1.7
Plugin using: Magento Mechanics Products Grid

Answer 1

I would use the observer, sales_quote_item_qty_set_after

And check if the configurable product exist in the cart, some information here.

https://stackoverflow.com/questions/18027524/get-simple-product-from-configurable-in-cart

And after that, remove the configurable product from the cart. And add the simple product.