Hi
I did the same as you said but the default quantity in the cart_summary.js still is 1. It cannot change to the quantity from the input in the shopping-cart-product-line.tpl ---- presta 1.5.4 ---
I need something like this in the cart too - when press '+' increase minimal_quantity of each product, '-' decreasing minimal_quantity.
Any one can help??? Where to manipulate those buttons?