This is the material Zoltan is talking about: http://www.gowesty.com/ec_view_details.php?id=2322&category_id=&category_parent_id= 

It's a vinyl sheet good.  In the Westy it's glued to a thin plywood panel (use spray upholstery adhesive), as well as other cabinets and the interior on later models.  You would need a panel to use as a model to cut another one, or fit up a piece of cardboard and make a template.  Maybe try to find someone parting out a Westy and buy the panel along with the trim that covers the rear edge, and the metal channels above the doors if those are missing.

Alternatively, find a friend who will let you remove his to use as a template.  It's not that hard to remove. 

Best idea, buy a complete Westy! ;-)

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Truls Erik Johnsen
Sent: Sunday, February 22, 2015 9:55 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Installing new headliner in a Westfalia Vanagon?

Hi guys,

Quick intro, since I'm "new" on the list (I think I was a part of the
conversation back in 2002-2004 or thereabouts, though). I'm
considering a 1985 Syncro Joker with a Westfalia pop-top with a 1.9l
WBX. It looks really good, but unfortunately the interior have been
used in another project. That includes the headliner as well.
Installing the interior should be fairly straightforward, I guess, but
the headliner gives me worries. So if any of you have experiences in
installing a new headliner in the Vanagon, espesially in a Westy, I
would really appreciate to hear some of your experiences.

Kind regards,

Truls Erik Johnsen
Ethnologist/Director of Brand Insight, Telenor Group
Bicycle Framebuilder, Johnsen Frameworks
www.johnsenframeworks.com
www.facebook.com/johnsen.frameworks
www.instagram.com/planetjohnsen