Thank you Ray, I manage to make it work. I also reproduce the AJAX update button in the Discount percentage select list and worked almost perfect. As you can see in the picture after I press the update link (in the second row) the value of the product updates but the RowDiscount which reflects the value of the discount remains the same in $0.50 and should update to $0. How can I make it update too? and also the delete link stopped working...
Thank you.
Regards,
Daniel