The home button is just a desktop switcher with custom icon to go to homescreen no. 1
I made a mistake in the actual screen no 1 there is no need (obviously) for a home screen button, I meant to put the app search widget there, downside is that widget doesn't work well in portrait.

It seems I have not made it clear enough that this is a real-life hildon-home configuration realizable with CSSU and apps from extras, and not some vaporware mockup.