Add product customized to cart

[mvilla_it]

Hi all, I am adapting a feature for a client, you need to sell by size. ie sold m2, for which I have the base price per m2, then the user enters the width and length.
I managed to do all the adjustments, but now I have the problem of how to insert it into the cart.
for example, the base price of a product unit was 10 €, but when the customer selects the measures, is the unit price of the unit is 2 €.
then when you add to cart, I inserted a product to 10 €, not 2 €.
I can alter the function as the insertion in the cart???.
I have found to insert into the cart, using two parameters, the in idProduct, idCombination. as I can do to add this product customized??

thank you very much
greetings