In my experience, REST APIs make it easier to communicate. If you are allowed to install modules, then a quick look at CPAN reveals http://search.cpan.org/~mcrawfor/REST-Client-88/lib/REST/Client.pm as a module for interacting with a REST endpoint. Given the fact that who ever made the script used Mechanize, more than likely you'll be making a POST or a GET call. Ask the share point admins to give you a sample request with headers. You'll more than likely have to get acquainted with REST but it's worth the while.