Install oScommerce Customer Private Messages Contribution Modifications

Contribution found here [login to view URL] I have already installed this contribution but its fairly basic. You can only send a pm to the customer from the customers details page which is a lot of admin and only one pm can be sent. Its not realy private messaging how we are used to on forums, its only for leaving a message. I need someone to modify this contribution or install a new script so the private message system is like what you find on forums, with inbox, sent, read etc. From admin side I need to send the pm from the customers order page, if the customer replies to a pm I need to be able to see the replies and make my reply on the same order page. The admin settings can be anywhere but message system needs to be on customer order page. From customer side the pm section must be in the customers account main page and they must be able to reply to pms and I can read it from admin. Its a 2 way pm, so there wont be any other users to pm.