A neat way of doing it. Links below to UK Vanagon owners who have done it:
http://www.brick-yard.co.uk/forum/westy-poptop-fit_topic49144.html
http://www.brick-yard.co.uk/forum/topic30479.html
UK firm that makes the repro kit:
www.vwelevation.com
PDF of the original German install:
Mosaik-Joker_Aufstelldach
Gifs of the components: