Customize osTicket to allow staff to answer via email

I have set up a LAMP environment running osTicket v1.8.0.2 to manage support request for my new product. I'll get an email once a customer opens a new ticket (via email) or sent a new message to an existing ticket, but if the staff member answers vie email, the answer is not forwarded by osTicket to the customer (to his email). So the answer sent from the staff member is added to the ticket history, but the customer doesn't receive it via email. Thus the staff member needs to log in to web interface to answer and that is not always possibile expecially if you're using a mobile device. I need to get someone who make the required changes to the PHP sources and sends me the changed files/classes. You'll need an email box where to send email in order to open a new ticket. This is the environment: osTicket Version v1.8.0.2 Server Software Apache/2 PHP Version 5.3.3-7+squeeze18 MySQL Version 5.1.73 PHP Extensions gdlib Used for image manipulation and PDF printing imap Used for email fetching xml Used for HTML email processing and XML API json Improves performance creating and processing JSON gettext Improves performance for non US-English configurations mbstring Highly recommended for non western european language content