Hi,
I think that the best way is to create a little plugin based on the function:
onAfterCartUpdate(&$this,&$cart,$product_id,$quantity,$add,$type,$resetCartWhenUpdate,$force)
Here is some documentation:
www.hikashop.com/support/documentation/6...umentation.html#cart
Else you can edit the file: "components/com_hikashop/views/product/view.html.php" function "init()" and replace:
$url = $this->_getCheckoutURL();
in the "checkout" case by:
index.php?option=com_hikashop&ctrl=product&task=updatecart&quantity=1&checkout=1&product_id=24&Itemid=212
Be careful, with the second option when you update HikaShop the changes will be lost.