its actually fairly easy.......read up on Tracking useing Combustions help file(F1)......that will be easiest for you cuz if we start jib-jabbering about how you do it it might confuse you considering we dont know any details on your project.....atleast give it a try....if you still have problems post them below....
after you have tracked your old footage in combustion(useing the help files, F1) copy those keyframes and paste them onto the correct transforms of your Photoshop layer.....