Properspell and PHP

When I first discovered Properspell I immediately wanted to use it on my sites, too.
Spell check suggestions for your search box on your site powered by Google. Have a look at their site (Properspell) to find out more.
And yes it was actually pretty easy to get to work. At least on HTML/javascript pages.
1. Sign up for a Google API key
2. Sign up for a Properspell API key using your oogle API key
3. Properspell will generate the code for you to insert into your pages

But my pages are generated by PHP. I did not get it to work.
Does anyone have a working implementation of Properspell using PHP? I haven't found any article googling.