According to GoWesty there is a threaded anchor behind the rear side panel.

"The reel mounts into a factory threaded hole - no drilling or
welding is required"

Perhaps see if the threaded hole exists on your Cdn van then use it
to hold your existing seat securely?

http://gowesty.com/ec_view_details.php?id=3218&search_phrase=child%20seat%20anchor&start=60

item kt-122

>I'm hoping the list can help me purchase the appropriate car seat for my
>toddler who has outgrown her rear facing infant seat.  I drive a 86 Westy