Discount coupon with minimum order value

-- url of the page with the problem -- : test.safka.co.nz
-- HikaShop version -- : 2.2.0.
-- Joomla version -- : 2.5.6
-- PHP version -- : 5
-- Browser(s) name and version -- : Firefox 24.0
-- Error-message(debug-mod must be tuned on) -- : no error message

Hi, I'm trying to set up a $10 discount coupon off a minimum $50 order - including taxes in all sums. No matter what setting I choose, it won't give me the discount if the untaxed total is less than $50, how to fix this?