Hi,
This option has been added to HikaShop 4.2.0 that we just released last week:
www.hikashop.com/support/documentation/5...ashop-changelog.html
We're still waiting or more feedbacks before activating the auto update for the 4.2.0. So if you want to update, you would first have to download the install package on our website via the menu My account>My subscriptions (after renewing your subscription as I can see it has expired) and then installing it on your website.
Note however that I already see the shipping and shipping address interfaces side by side on your checkout:
monosnap.com/file/mloR2nmPMVYxBiOPuGhsAmNBgYWpeg
And if you're talking about the registration/guest form, even with the separator option, it won't allow you to have the shipping address fields next to the billing address fields in the registration form as the separator can only be added between two views, not inside views.