What should I do to get PVC onto the @ISA array?

Technically, @ISA arrays are private to their classes, and cannot be relied on to directly determine inheritance. The correct manner is to use the ->isa() method which can be overriden by classes (as is the case with Object::InsideOut) to provide correct inheritance information.

Only Object::InsideOut classes are put into the @ISA array. Foreign inheritance is handled via Object::InsideOut's version of the ->isa() method, and in its AUTOLOAD subroutine.