Tosh, I live in Germany and WFP is virtually nonexistant here. I only have a rough idea of WFP and am trying to find out as much as I can, just wondered why a piece of kit like that would end up on Ebay.
Have you had a look at Matt's DIY site? That used to give a good explanation of how all this stuff works; it's simple once you understand the principles; honestly.
I'm not sure if I can post a link to it here, but if you have a search for Matt's posts, I'm sure you'll be able to e-mail him for a link.
Also, where in Germany are you; just out of interest? I've spent years in Germany as a squaddie. My postings were Bielefeld, Duisburg, Verden (near Hannover), Celle and Belsen (both near the infamous concentration camps).
I seem to remember there's loads of flats in Germany; probably because most of the houses were bombed during WW2; but most of them have balconies; which could be a pain.