you could dod this using the add to cart server behavior.
first make sure to create a binding for each URL variable, on the bindings panel, click the plus button, select URL variable, then add the name for the binding, rinse and repeat for each URL variable.
then go to the server behaviors tab and click the plus button, select eCart -> Add to Cart -> Add to cart.
for the cart columns, bind each one to the corresponding URL variable.