I really want to thank those who responded to my very needy request.Very
timely. The archives is almost empty on this subject(as far as I could
search). My early WBX heater box has the flaps sealed inside, and removal
of the box(6 hr.) is needed ot replace the gaskets. Not so on late boxes.
I am sure that bad seals cause many vanagon owners to go around with cold
feet in winter, and hot feet in summer. Replacement of these gaskets on the
late box is EZ. Just lean down and actually look at where the flaps hinge
at. You will see little plastic pins that will relase the flaps.
Replacement of the foam gasket is by little plastic snap thingies. No glue
needed.You can do it in an evening. The VW engineer that fixed this
situation, must have needed to replace the gaskets on an early box,
himself.  This new info in the archives will help many tempature
challenged,unhappy, vanagon owners.

I am going to use weather stripping cement for my gaskets.It is a favorite
product of mine. Sticks tight for years. Even in the hot interior of a car
in summer. Most glues have a very low tempature range,and may not hold up.

 As for the foam, I now have several choices to check out. Once again,
these OEM gaskets have a skin on them for some reason. Must be for
durability and sealing. A flat gasket must seal better than a bunch of foam
bubbles?  Whebn I put it all back together, I am confdent I will have done
the repair correctly.