Coding Help For Affiliate Program

I am creating my own affiliate program for my information products and I am stuck.? I am using Post Affiliate Pro and the coding to customize what I need is beyond what I or my web design guy know what to do. One of my collgues in my business has a system similar to what I need to create so we can look at how that functions and go from there.? In a nutshell there is an affilaite sign up page that asks for you to create a username and password.? Once you login the username is used in a sub domain to promote a partiular product. So if I put my username as "sam"? when I log in to the system my website to promote the product would be:? http:/[login to view URL] All of the graphic dsign and simple integration elemnets we can handle and we have a base program to use so we don't have to do all of the affiliate tracking and payment set up. I am not married to this system and am completely opneminded on which way to go. Thank you.