Update product prices in cart

Hi
first : sorry for my poor english

My products have differents prices depending of the statu of the client. If the client isn't logged the products are full prices. if he is logged, there is a discount applied on some product. So the discount is applied on the products not the entire cart.
My problem: when the client is not logged and he put some products in his caddie, then he log himself, the checkout cart show the product price with full prices it doesn't update himself with news prices whith client's discount. I would like to know if there is a way to update the product prices and then the whole cart.

Thanks

Yes, you would store both prices in the cart when it is inserted and create a calculation to change the price in the cart based on a session variable, that way they could log in and get the new price at any time.

So it mean that i have to store every possible discounted prices in the cart, as there are 3 to 5 discount rates. there is no function to update the prices in the cart ?

There is no server behavior that will loop through and update the cart.

If you are familiar with php you could write the necessary code pretty quickly, but there is no other way to do it without hand coding.