I want to make sure I note this here in case anyone missed it.

Thanks to the ultra-industrious Diana Stoneman, we have a workaround for this. Read this post and follow the directions. And then drop by Diana’s site to extend your fondest regards for her excellent contribution to the site.

I’m still lobbying Squarespace to add this functionality to an upcoming upgrade, but in the meantime, this is an awesome workaround.