I feel dirty for even suggesting it, but perldoc perlsub tells you how to override builtin functions. I hacked up an example overriding 'print' that called CORE::print twice - once to STDOUT and once to a filehandle, so I know 'print' can be overridden. That won't work for you: I needed to call my print as &print and you said you've no access to the sub.

I feel even dirtier suggesting you look into importing your print function into CORE::GLOBAL.

It's definitely dangerous, but hey, the functionality is there.