Add KeyCaptcha to registration form (in checkout)

-- HikaShop version -- : 2.3.2
-- Joomla version -- : 3.3.3
-- PHP version -- : 5.3.29

Your documentation says that Hikashop integrates with KeyCaptcha.

So, I installed & enabled the KeyCaptcha plugin, and entered the keys, and selected it as my default captcha in Joomla Global Configuration. On the front end when I go to the standard Joomla "create a new account" page, the Keycaptcha appears.

But, when I start the Hikashop checkout process, on the account page (the one with Log In on the left and Create New Account on the right), KeyCaptcha does not appear. Users can create a new account without having to do the captcha. Obviously this is a big security problem.

Do I have to do something else to make KeyCaptcha appear on this page? I've looked through all the Hikashop configuration but I don't see anything.