Well, the best thing to do, IMHO, is to complain to the people that have disabled it, and if they won't budge, complain to their managers. That's just ridiculous to not give the developer access to that function.
If they won't budge at all with that, then you should be able to use a few other functions to get the info you need. All of the functions that pertain to php options and information are documented here: http://us3.php.net/manual/en/ref.info.php . For example, if you want to know what modules (extensions) are available you could run get_loaded_extensions(). That is... if they haven't disabled that as well.