Verisign PFPRO API & PHP: How to ensure hitting "STOP" in the browser will not kill the transcation

I've not been able to find anywhere a good use of the pfpro functionality in PHP. No where do any of the scripts ensure that the script goes through it's full execution. One person's solution was just to exec the pfpro binary in the background, passing it the necessary arguments. This seems insecure. I'd like to use PHP's pcntl_fork(), however, I read that using it in PHP where PHP is an Apache module could produce unpredictable results.. Is anyone using pcntl_fork with the pfpro stuff in a PHP compiled as a module.....successfully? Thanks Erik Osterman