cre loaded/os commerce paypal express/ website payments pro install

i am running cre loaded 6.2 (patch 13.1), and need paypal website payments pro installed. website is modified from standard install, and care should be made to retain exact look/operation of site. when paypal payments pro is installed (and live - not sandbox), i will test to ensure proper operation. it must do chekout and return to site properly, while recording orders properly, and sending notification of order properly. this is basically how paypal payments pro should work out of the box, but you may need to modify code/adjust to make it work properly. this is for competent php coders only. if you are not familiar with paypal api's, and installation of website payments pro into cre loaded, do not apply. if you've done a paypal payments pro install in cre loaded before, this should be an easy task. modifications will be done on live server, with website processing orders, so if there will be any major down time, please notify me in advance. minor downtime (less than 180 minutes total) is fine and to be expected. you will need to backup site, and restore if you should run into any complications that would cause site to not work as it did when you started. i will need to be notified of any changes made in code outside of the 'paypal' directory.