I'm sure Dennis will answer your question himself but let me add these
comments.
First, this is a subject that has more in the archives than any other.
Second, go to roadhaus.com and follow the link on tire reviews, lots of info
there.
Third, if you bought those tires new from a dealer I would like to know the
dealer so I don't try to do business with them.  Go professional shops like
Discount/Americas Tires won't sell you or mount passenger car tires on a
Vanagon.
And last, I take my '90 Westy to a local VW dealer for wheel alignment.
Happens to be one of the few dealers around anywhere that has both a
competent and fair service department.  Each time (twice) I've gone in for
alignment, the first thing the service writer does is go out and check to
see what tires I'm running.  I asked what they would do if I were running
the wrong type or size tires, he said "We wouldn't touch the alignment and
would advise you to get safe tires".
There are many on this list that do or have run P tires and say they are
fine.  YMMV