package Caller::CompiledIn;
sub origCaller { shift(@_)->_protected_method(); }

package Protected::CompiledIn;
sub origProtected { my $self= shift(@_)->_PROTECTED(); ... }

package main;

@Protected::Class::ISA= 'Your::Uber::BaseClass';
*Protected::Class::_protected_method= \&Protected::CompiledIn::origProtected;

@Caller::Imported::ISA= 'Protected::Class';
*Caller::Imported::importedCaller= \&Caller::CompiledIn::origCaller;

my $obj= bless [], 'Caller::Imported';
$obj->importedCaller();